Can I send data to prefill a form for signature

I am using Filemaker and would like to create an invoice in the software and via API send data to pre-fill a form that the user can then sign.. That form could be pulled back into filmmaker. I know the latter is achievable but asking about uploading data to a form?

Thank you

Signature field stores signature as image and unfortunately, you can't prefill an image in Jotform.