Submit W-8BEN-E tax form

This POST endpoint is used to submit a W-8BEN-E tax form for a specific user identified by their user_token. The W-8BEN-E form is used by foreign entities to certify their foreign status, chapter 3 status, chapter 4 (FATCA) status, and claim tax treaty benefits (if applicable). Basic information (name, address, phone) is retrieved from the user's existing profile.
To use this endpoint, you need to provide the user_token as a parameter in the URL Path and the W-8BEN-E form data in the request body.