How can I prefill a signed document?

Hi Jotform Support Team,

We’re building an automated enrollment agreement workflow and need to pre-fill a Jotform Sign document (not a regular form) with student data before sending it for signature. The student should see the actual PDF pre-populated, then sign and submit. We orchestrate everything with Zapier, and store the signed PDF back in FileMaker.

Could you please advise on the following?

1. Prefill for Sign docs

• Does Jotform Sign support pre-filling text/number/date fields via API, URL parameters, or Tables Prefill?

• If yes, can you share docs and an example payload showing how to reference field IDs/keys on a Sign document?

2. Hidden identifiers

• Can we include a hidden field (e.g., UUID/StudentID) on the Sign doc that’s returned in the “document completed” event or accessible via the API, so we can match back to the correct student?

3. Send invite with prefill (API)

• Is there an endpoint to send a Sign invite with prefilled values in one call?

4. Retrieving the executed PDF

• From the completion webhook or API, what’s the best way to fetch a direct link to the executed PDF? Do we need any special headers to download it programmatically?

5. If prefill isn’t supported in Sign

• What’s your recommended workaround to preserve the “see the actual PDF” experience? (e.g., Smart PDF alternative, or a signing order where an internal user pre-populates fields before sending to the student.)

Happy to provide our document/form IDs if that helps.

Thanks so much for the guidance!

Hi steveslater,

Thanks for reaching out to Jotform Support. Regarding your questions about pre-filling a Jotform Sign document with student data before sending it for signature, currently, Jotform Sign documents do not support pre-filling fields via the API, URL parameters, or Prefill integrations. The Prefill feature and related automations currently apply only to regular forms. Similarly, hidden fields such as UUID or StudentID are not supported in Sign documents and can’t be passed through or retrieved via API or Prefill tools.

The Jotform API is not yet supported for Sign documents, including sending invitations or prepopulating data. If you need to automate your workflow, the only available automation method for Sign documents is through webhooks, which can notify you when a document has been completed. The webhook payload includes the document ID and a direct download link to the signed PDF, allowing you to track or retrieve the executed file programmatically.

As a workaround to maintain a “see the actual PDF” experience, you have two options:

• Smart PDF Form: You can upload your original PDF and map it to form fields. Smart PDF supports prefill via URL parameters or the Prefill tool. However, signers will fill in an online form interface, not the actual PDF directly. Their answers are automatically placed into your PDF layout upon submission.
• Two-signer in Jotform Sign: Assign the prefill fields to yourself or an internal user as the first signer, fill them in manually, and then send the document to the student as the second signer. This ensures the student receives a Sign document that already shows the prefilled information before signing.

Let us know if you have any other questions or need additional help.