Request payments

Number of APIs: 5

1. Add payment request field PUT {{url}}/document/{{document_id}}

2. Send an invite to sign (payment request fixed) POST {{url}}/document/{{document_id}}/invite

3. Update merchant account POST {{url}}/organizations/{{organization_id}}/merchantaccount

4. Get merchant account GET {{url}}/organizations/{{organization_id}}/merchantaccount/{{merchant_account_id}}

5. Delete merchant account DELETE {{url}}/organizations/{{organization_id}}/merchantaccount/{{merchant_account_id}}