How you request an account-specific token depends on the type of authentication you are using.

Basic authentication

When you call Get basic authentication access token endpoint, you need to include the account ID in the body parameter account_id. See Initial authentication for more information.

OpenID authentication

To generate JWTs, you should already have configured a program. To generate an account-specific JWT, you pass the account ID in the uid field when calling this program. Then, when you use the resulting JWT to request an access token, the token you get back will be account-specific. For more information, refer to Creating a JWT.