You click the first field. Nothing. You tab. Nothing. The form looks like a form but behaves like a picture.
There are two completely different forms problems here. Either there are no real fields (it's a picture of a form), or the fields exist but are locked.
What's actually going wrong
Flat form. The PDF shows blank lines and boxes but has no interactive fields. Common with forms that were scanned, or templates exported without form layers. Locked form. Fields exist but the PDF's permissions block input.
To tell the difference, try clicking exactly where a field should be (centre of a blank line). If a cursor appears, the field exists and it's a permission issue. If nothing happens, the form is flat.
The quick fix
For flat forms, treat them as documents not forms. Edit the PDF in Flint and use the text tool to type directly onto the page. Place your text on the blank lines. Save the edited file. It's not a 'real' filled form but the result is the same — your information on the document.
For locked forms, unlock with the owner password if you have it, then fill normally. If you don't have the password, ask the sender for an unlocked version.
If that didn't work
For forms you need to submit electronically and that don't accept typed-on-text, request a form-enabled version from the issuer. Many government and legal forms exist in both versions.
For forms with signing requirements that aren't accepting your signature, use sign PDF — Flint flattens signatures into the page reliably, working on forms that block traditional signature fields.
Prevent it next time
When sending forms for others to fill, use real interactive fields, not just blank lines on a template. When sending PDFs, don't apply permission locks that block form filling. And when receiving forms, ask whether they're interactive before printing or starting to fill.
FAQ
Why does my PDF form look fillable but isn't?
It's a 'flat form' — visual lines without real fields underneath. Type onto the page using Flint's editor and you get the same result as filling a real form.
Can I add fields to a flat PDF?
In principle yes, with form-builder tools. For most users, typing onto the page in Flint's editor is faster and produces equivalent output.
Why does typing in a form field do nothing?
Either the field is locked (permissions), the form is reader-only, or your viewer doesn't fully support form interaction. Try Flint's editor which handles most cases.
Will my flat-form fills survive sending the file?
Yes, once flattened. Flint's editor saves filled text as part of the page content, not an editable overlay. The recipient sees exactly what you typed.
Flat or locked, every form fills somehow. Open in Flint's editor and type, sign, save.