Hi John.
Data sync module is a simple service that will allow you to manipulate data in recordsets.
You'll have to create request with data to save_record.php
.
However if you wish to create more complicated logic than just adding new records, maybe it'll be better to create your own custom script to add data to EPESI. With simple secret token as verification.
It depends on the fields used in the form. Would you like to perform contacts lookup, create new contact each time, etc.
If you'll describe your form and workflow in details, I'll be able to tell more about the best solution in my opinion.
Best regards,
Adam