PDF forms come in two flavours, and knowing which you have makes filling them painless.
Interactive vs. flat forms
- An interactive form (AcroForm) has real clickable fields — text boxes, checkboxes, dropdowns. You click and type.
- A flat form is just a printed-looking page with lines and boxes but no interactive fields. To "fill" it you overlay your own text.
How to fill a form in PDFelly
- Open the Fill Form tool and add your PDF.
- For interactive forms, click each field and enter your details.
- For flat forms, add text boxes wherever you need them and type.
- Apply and download the completed form.
Getting alignment right
- Zoom in to place overlay text precisely on the lines.
- Match the font size to the form's printed text for a tidy look.
- For checkboxes on flat forms, a simple "X" or tick overlay works well.
Finish strong
Once complete, add your signature if required, then flatten the document so your entries become permanent and cannot be edited by the recipient. As always, the form — often full of personal data — stays on your device throughout.
Identifying which kind of form you have
Click on a blank space in the form. If a cursor appears and you can type, it is an interactive form with real fields. If nothing happens, it is a flat form — essentially a picture of a form — and you will overlay your own text. Knowing which you have removes the frustration of trying to click into fields that do not exist.
Filling flat forms cleanly
For flat forms, zoom in and place text boxes directly on the lines, matching the font size to the printed text so your entries look like they belong. For checkboxes, a small "X" or tick overlay is clearest. Take a moment to align everything; tidy placement is the difference between a form that looks completed and one that looks scribbled on.
Finishing: sign, then flatten
Many forms need a signature as well as data. Fill the fields first, add your signature where required, then flatten the document so your entries and signature become permanent and cannot be altered by whoever receives it. Because forms are full of personal information, doing all of this in the browser keeps that data on your device.
Frequently asked questions
How do I know if my form is interactive or flat?
Click a field. If you can type into it, it is interactive. If nothing happens, it is flat and you add text overlays instead.
Can I fill a form that has no clickable fields?
Yes. Add text boxes wherever you need them and type — useful for scanned or flattened forms.
How do I stop the recipient editing my entries?
Flatten the completed form so your text becomes static page content.
Is my personal data uploaded?
No. Form filling happens entirely in your browser; nothing is transmitted.
Saving time on forms you fill repeatedly
Some forms come back again and again — the same expense template, the same intake sheet, the same application format. For these, a little setup saves a lot of repeated effort. Keep a blank master of the form so you always start clean. Note which fields change every time and which stay the same, and consider keeping your standard details somewhere handy to paste in quickly. For flat forms you fill by overlaying text, remember the positions and sizes that worked so the next copy lines up the same way. When a form must be returned looking official, fill it, add any required signature, and flatten before sending so your entries cannot be altered. Because forms are dense with personal and financial information, the fact that everything happens locally is not a minor detail — it means the data you type is never transmitted while you complete the document.
Related guides
- How to Password-Protect a PDF (and What the Encryption Actually Does)
- How to Remove a Password From a PDF You Own
- How to Redact Sensitive Information From a PDF Properly