Retrieves the custom field information for the specified envelope. You can use these fields in the envelopes for your account to record information about the envelope, help search for envelopes, and track information. The envelope custom fields are shown in the Envelope Settings section when a user is creating an envelope in the DocuSign member console. The envelope custom fields are not seen by the envelope recipients.
There are two types of envelope custom fields, text, and list. A text custom field lets the sender enter the value for the field. With a list custom field, the sender selects the value of the field from a pre-made list.
The external account number (int) or account ID Guid.
The envelope's GUID. Eg 93be49ab-afa0-4adf-933c-f752070d71ec