Is called if documentType is "html" (see /settings). Should return iframe string which should direct the user to the 3rd party system where he/she can finalize and send the e-sign to the recipient.
Request body.data contains the information of the file and recipients
Document id corresponding to e-sign in Upsales. Using this the integration can make a request to Upsales to get the full e-sign. On the e-sign object, the document ID can be found which you can use to open the correct e-sign in the iFrame.
The response has to be a string with the iFrame HTML where the user can edit and send their e-sign
<iframe style=“width: 100%; height: 100%; border: none;” src=“URL_TO_ESIGN”></iframe>