diff --git a/packages/core/types/src/fulfillment/mutations/shipping-option.ts b/packages/core/types/src/fulfillment/mutations/shipping-option.ts
index bf02f1f4f25f1..d697838eb6a1c 100644
--- a/packages/core/types/src/fulfillment/mutations/shipping-option.ts
+++ b/packages/core/types/src/fulfillment/mutations/shipping-option.ts
@@ -136,23 +136,24 @@ export interface CalculateShippingOptionPriceDTO {
   provider_id: string
 
   /**
-   * The option data from the provider.
+   * The `data` property of the shipping option.
    */
   optionData: Record<string, unknown>
 
   /**
-   * Additional data passed when the price is calculated.
-   *
-   * @example
-   * When calculating the price for a shipping option upon creation of a shipping method additional data can be passed
-   * to the provider.
+   * The shipping method's `data` property with custom data passed from the frontend.
    */
   data: Record<string, unknown>
 
   /**
    * The calculation context needed for the associated fulfillment provider to calculate the price of a shipping option.
    */
-  context: CartDTO & { from_location?: StockLocationDTO } & Record<
+  context: CartDTO & { 
+    /**
+     * The location that the items will be shipped from.
+     */
+    from_location?: StockLocationDTO
+  } & Record<
       string,
       unknown
     >
diff --git a/packages/core/types/src/fulfillment/provider.ts b/packages/core/types/src/fulfillment/provider.ts
index 9b06c992adfe6..5fdbe94c16273 100644
--- a/packages/core/types/src/fulfillment/provider.ts
+++ b/packages/core/types/src/fulfillment/provider.ts
@@ -2,7 +2,8 @@ import { CalculateShippingOptionPriceDTO } from "./mutations"
 
 export type FulfillmentOption = {
   /**
-   * The option's ID.
+   * The option's ID. This ID can be an ID in the third-party system relevant
+   * for later processing of fulfillment.
    *
    * @example express
    */
@@ -15,7 +16,15 @@ export type FulfillmentOption = {
 }
 
 export type CalculatedShippingOptionPrice = {
+  /**
+   * The calculated price.
+   */
   calculated_amount: number
+  /**
+   * Whether the calculated price includes taxes. If enabled, Medusa will
+   * infer the taxes from the calculated price. If false, Medusa will
+   * add taxes to the calculated price.
+   */
   is_calculated_price_tax_inclusive: boolean
 }
 
diff --git a/packages/core/utils/src/fulfillment/provider.ts b/packages/core/utils/src/fulfillment/provider.ts
index 7d152431ec507..22582d2ccb98a 100644
--- a/packages/core/utils/src/fulfillment/provider.ts
+++ b/packages/core/utils/src/fulfillment/provider.ts
@@ -8,8 +8,8 @@ import {
 /**
  * ### constructor
  *
- * The constructor allows you to access resources from the module's container using the first parameter,
- * and the module's options using the second parameter.
+ * The constructor allows you to access resources from the [module's container](https://docs.medusajs.com/learn/fundamentals/modules/container) 
+ * using the first parameter, and the module's options using the second parameter.
  *
  * :::note
  *
@@ -34,6 +34,7 @@ import {
  * }
  *
  * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
+ * // other properties...
  *   protected logger_: Logger
  *   protected options_: Options
  *   // assuming you're initializing a client
@@ -90,9 +91,15 @@ export class AbstractFulfillmentProviderService
   }
 
   /**
-   * This method retrieves the shipping options this fulfillment provider supports.
+   * This method retrieves a list of fulfillment options that this provider supports. Admin users will then choose from these options when
+   * they're creating a shipping option. The chosen fulfillment option's object is then stored within the created shipping option's `data` property.
+   * The `data` property is useful to store data relevant for the third-party provider to later process the fulfillment.
+   * 
+   * This method is useful if your third-party provider allows you to retrieve support options, carriers, or services from an API. You can then
+   * retrieve those and return then in the method, allowing the admin user to choose from the services provided by the third-party provider.
    *
-   * @returns The list of fulfillment options.
+   * @returns The list of fulfillment options. Each object in the array should have an `id` property unique to an item, and a `name` property
+   * that's used to display the option in the admin.
    *
    * @example
    * // other imports...
@@ -101,15 +108,15 @@ export class AbstractFulfillmentProviderService
    * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
    *   // ...
    *   async getFulfillmentOptions(): Promise<FulfillmentOption[]> {
-   *     return [
-   *       {
-   *         id: "express"
-   *       },
-   *       {
-   *         id: "return-express",
-   *         is_return: true
-   *       }
-   *     ]
+   *     // assuming you have a client
+   *     const services = await this.client.getServices()
+   * 
+   *     return services.map((service) => ({
+   *       id: service.service_id,
+   *       name: service.name,
+   *       service_code: service.code,
+   *       // can add other relevant data for the provider to later process the shipping option.
+   *     }))
    *   }
    * }
    */
@@ -179,17 +186,21 @@ export class AbstractFulfillmentProviderService
   }
 
   /**
-   * This method indicates whether a shippin option's price is calculated during
-   * checkout or is fixed.
+   * This method validates whether a shippin option's price can be calculated during checkout. It's executed when the admin user creates a shipping
+   * option of type `calculated`. If this method returns `false`, an error is thrown as the shipping option's price can't be calculated.
+   * 
+   * You can perform the checking using the third-party provider if applicable. The `data` parameter will hold the shipping option's `data` property, which
+   * includes the data of a fulfillment option returned by {@link getFulfillmentOptions}.
    *
    * @param data - The `data` property of the shipping option.
-   * @returns Whether the price is calculated for the shipping option.
+   * @returns Whether the price can be calculated for the shipping option.
    *
    * @example
    * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
    *   // ...
-   *   async canCalculate(data: any): Promise<boolean> {
-   *     return data.custom_type !== "fixed"
+   *   async canCalculate(data: Record<string, unknown>): Promise<boolean> {
+   *     // assuming you have a client
+   *     return await this.client.hasRates(data.id)
    *   }
    * }
    */
@@ -198,15 +209,22 @@ export class AbstractFulfillmentProviderService
   }
 
   /**
-   * This method calculates the price of a shipping option, or a shipping method when it's created.
-   *
-   * The Medusa application uses the {@link canCalculate} method first to check whether the shipping option's price is calculated.
-   * If it returns `true`, Medusa uses this method to retrieve the calculated price.
-   *
-   * @param optionData - Shipping option data from the provider, the `data` property of a shipping option.
-   * @param data - Additional data passed when the price is calculated.
-   * @param context - The context details, such as the cart or customer.
-   * @returns The calculated price
+   * This method calculates the price of a shipping method when it's created or its cart is refreshed.
+   * 
+   * In this method, you can send a request to your third-party provider to retrieve the prices. The first 
+   * parameters holds the `data` property of the shipping method's shipping option, which has fulfillment 
+   * object data returned by {@link getFulfillmentOptions}.
+   * 
+   * The second parameter holds the `data` property of the shipping method, which has data returned by {@link validateFulfillmentData}.
+   * It can also hold custom data passed from the frontend during checkout.
+   * 
+   * So, using both of these data, assuming you're storing in them data related to the third-party service,
+   * you can retrieve the calculated price of the shipping method.
+   *
+   * @param optionData - The `data` property of a shipping option.
+   * @param data - The shipping method's `data` property with custom data passed from the frontend.
+   * @param context - The context details, such as the cart details.
+   * @returns The calculated price's details.
    *
    * @example
    * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
@@ -232,15 +250,17 @@ export class AbstractFulfillmentProviderService
    * `data` property, it's stored in the fulfillment's `data` property.
    *
    * The `data` property is useful when handling the fulfillment later,
-   * as you can access information useful for your integration.
+   * as you can access information useful for your integration, such as the ID in the
+   * third-party provider.
    *
-   * You can also use this method to perform an action with the third-party fulfillment service.
+   * You can also use this method to perform an action with the third-party fulfillment service
+   * since a fulfillment is created, such as purchase a label.
    *
    * @param data - The `data` property of the shipping method this fulfillment is created for.
    * @param items - The items in the fulfillment.
    * @param order - The order this fulfillment is created for.
    * @param fulfillment - The fulfillment's details.
-   * @returns The data to store in the fulfillment's `data` property.
+   * @returns An object whose `data` property is stored in the fulfillment's `data` property.
    *
    * @example
    * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
@@ -260,7 +280,7 @@ export class AbstractFulfillmentProviderService
    *
    *     return {
    *       data: {
-   *         ...data,
+   *         ...(fulfillment.data as object || {}),
    *         ...externalData
    *       }
    *     }
@@ -280,19 +300,22 @@ export class AbstractFulfillmentProviderService
    * This method is used when a fulfillment is canceled. Use it to perform operations
    * with the third-party fulfillment service.
    *
-   * @param fulfillment - The fulfillment's details.
+   * @param data - The fulfillment's `data` property.
    *
    * @example
    * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
    *   // ...
-   *   async cancelFulfillment(fulfillment: any): Promise<any> {
+   *   async cancelFulfillment(data: Record<string, unknown>): Promise<any> {
    *     // assuming the client cancels a fulfillment
    *     // in the third-party service
-   *     await this.client.cancel(fulfillment.id)
+   *     const { external_id } = data as {
+   *       external_id: string
+   *     }
+   *     await this.client.cancel(external_id)
    *   }
    * }
    */
-  async cancelFulfillment(fulfillment: Record<string, unknown>): Promise<any> {
+  async cancelFulfillment(data: Record<string, unknown>): Promise<any> {
     throw Error("cancelFulfillment must be overridden by the child class")
   }
 
@@ -321,17 +344,19 @@ export class AbstractFulfillmentProviderService
    * `data` property, it's stored in the fulfillment's `data` property.
    *
    * The `data` property is useful when handling the fulfillment later,
-   * as you can access information useful for your integration.
+   * as you can access information useful for your integration. For example, you 
+   * can store an ID for the fulfillment in the third-party service.
    *
-   * Use this method to perform actions necessary in the third-party fulfillment service.
+   * Use this method to perform actions necessary in the third-party fulfillment service, such as
+   * purchasing a label for the return fulfillment.
    *
    * @param fulfillment - The fulfillment's details.
-   * @returns The data to store in the fulfillment's `data` property.
+   * @returns An object whose `data` property is stored in the fulfillment's `data` property.
    *
    * @example
    * class MyFulfillmentProviderService extends AbstractFulfillmentProviderService {
    *   // ...
-   *   async createReturnFulfillment(fulfillment: any): Promise<any> {
+   *   async createReturnFulfillment(fulfillment: Record<string, unknown>): Promise<any> {
    *     // assuming the client creates a fulfillment for a return
    *     // in the third-party service
    *     const externalData = await this.client.createReturn(
@@ -340,7 +365,7 @@ export class AbstractFulfillmentProviderService
    *
    *     return {
    *       data: {
-   *         ...fulfillment.data,
+   *         ...(fulfillment.data as object || {}),
    *         ...externalData
    *       }
    *     }