# Exemption Certificate Management use cases

Source: https://developer.avalara.com/products/ecm/integration-guides/document-management/vbf7601457386153/

Guide: Exemption Certificate Management (ECM)

# Exemption Certificate Management use cases

Explore use cases for ECM, including task descriptions and example REST API calls.

This section describes the use cases that you must complete and include with your functional review demo. Each use case provides a description of the task and an example REST API call.

Tip

The APIs in these use cases require your `companyId` in the request URL. If you don't know your `companyId`, you can retrieve it using one of the following methods:

-   Run the [QueryCompanies](https://developer.avalara.com/api-reference/avatax/rest/v2/methods/Companies/QueryCompanies/). The response will include the `id` for each company in your account.
-   Select your company in the AvaTax UI. The `companyId` will be the second set of digits in the URL. For example: https://admin.avalara.com/cup/a/{accountId}/s/{companyId}/