Ultimately I'm simply looking to have a customer fill out a form, this will update the CRM record and trigger a mailmerge template to send a contract through Zoho Sign. I want this process to be as automated as possible (currentlly I can automate the form to CRM update but the mailmerge to Sign is giving me issues).

I've been getting better writing custom functions so I figured I'd give that a try but I cannot find any documentation on using mail merge in a CRM workflow or mail merge with a CRM with a customer function or using Sign and Writer with custom functions.

From what I can find just messing around making a function I can see a merge is possible with writer but when I see code like this and no documentation I have no idea the parameters for the string and bigint fields and guesswork hasn't gotten me anywhere. Is there documentation out there I'm missing? 

zoho.writer.getDocuments(<STRING>, <BIGINT>, <BIGINT>, <STRING>, <STRING>);