Building Forms
File uploads & signatures
Collect documents, images, and drawn signatures — formbase stores them alongside each submission.
File upload
The File Upload field lets respondents attach files to their submission. Type / on the canvas and pick File Upload.
Click the drag handle next to the field and open Validation to set its rules:
| Rule | What it does |
|---|---|
| Min files | How many files the respondent must attach. |
| Max files | The ceiling. Set it to 1 and the picker stops being multi-select. |
| Max size (MB) | Per-file size limit. Leave it empty and only the platform ceiling applies. |
| Accepted types | Pick from the list — .pdf, .doc/.docx, .xls/.xlsx, .ppt/.pptx, .csv, .txt, image/*, .jpg/.jpeg, .png, .gif, .svg, .webp, video/*, .mp4, audio/*, .mp3, .zip, .rar. Pick several to allow several. Leave it empty to accept any file. |
The field shows respondents what it expects — “Accepted files: .pdf, .png”, “Max 5 MB”, “2-4 files” — so the rules double as the hint.
File validation rules
Size, count, and type are checked in the browser as the respondent picks a file; a violation shows an inline error and blocks submission. Two more limits apply on the server and cannot be raised per field:
1 GiB per file, whatever your Max size says.
Your workspace storage quota — 100 MB on Free, 500 GB on Pro and Business. When the owner is out of room the form refuses uploads with “This form is currently unable to accept file uploads,” so respondents cannot finish. See limits & quotas.
Uploaded files are stored with the submission. Open a submission in the inbox to view or download them.
File uploads in conditional logic
A File Upload field offers two logic conditions: has file and has no file. Use them to show a follow-up question only when nothing was attached, or to skip a page once the document is in.
Signatures
The Signature field captures a drawn signature. Type / and pick Signature from the slash menu. Respondents draw with a mouse, trackpad, or finger. formbase stores the result as an image, viewable and downloadable from the submission inbox.
A signature makes the submission final
Any form version that contains a Signature, Payment, or Schedule appointment field turns off edit after submit for submissions made against it. Respondents cannot reopen and change what they signed.
Signatures in conditional logic
Signature fields support two logic conditions: is signed and is not signed. Use them to show a confirmation page only after a waiver is signed, or to require extra info when a signature is missing.
Signatures and partial responses
Signature data is not shown for partial (in-progress) responses: the inbox hides the thumbnail and exports leave the column empty until the respondent submits.
When to use signatures
Signatures work well for any form that needs documented consent or acknowledgment:
- Contracts and agreements
- Consent forms (medical, research)
- Liability waivers
- Approval workflows
Common patterns
Job application — a File Upload for the resume (accept .pdf and .doc, .docx) plus a second upload for the cover letter
Insurance claim — a File Upload set to
image/*for photo evidence, with a high Max files so claimants can document the damage properlyContract signing — a Documents block holding the contract, then a Signature field under it
Event registration — an ID photo upload (images only, Max files 1) alongside the contact fields
Uploads count toward your storage quota
Every file, including signatures and generated PDFs, counts against the workspace owner’s storage. Set conservative size limits if you collect large files regularly.