How to fill a PDF that isn't fillable

You open a form, click a blank line, and nothing happens. The PDF is flat: either it was flattened, or it is a scan. You can still complete it by placing text on top of the page. Here is how, with four free options.

Updated October 2026 · 6 min read

How to tell if a PDF is fillable

Open it in Chrome or Acrobat Reader and click a blank line or box. In a fillable PDF, a field highlights and a text cursor appears. Many viewers also tint the fields light blue or grey when the file opens.

If clicking does nothing, the form is flat. Another check: try to select the printed labels with your mouse. If you can, the page has real text. If the whole page selects as one block, or nothing selects, it is a scanned image.

Why forms end up flat

Two common causes. First, someone printed the form to PDF (or used "Save as PDF" from a word processor), which keeps the look but drops the interactive fields. This is also called flattening. Second, someone printed a paper form and scanned it, so the page is just a photo of a form.

Either way, the fix is the same: put new text on top of the page and save a new copy. It is not OCR, and that matters. Scanned text stays a picture and does not become editable. You are adding to the page, not editing what is already on it.

Option 1: Chrome's built-in Add text

Recent Chrome versions can add text to a PDF in the built-in viewer. Per Google's Manage PDFs in Chrome help page (as of October 2026), you select Add text, choose a font, style and colour from the sidebar, then click where you want the text.

Good for: a quick one-line form with nothing to install. Limits: the tools are simple. Check that you can place small text precisely and tick boxes the way you need before relying on it for a long form.

Option 2: Mac Preview text boxes

1. Open the PDF in Preview and click the Markup button.
2. Choose the Text tool (the box with a T) and click on the page.
3. Type, then drag the box onto the line. Use the font controls to shrink it.
4. For a box, type an "X" in a text box. Then File → Save.

Good for: Mac users. Limits: Mac only, and no real check-mark tool.

Option 3: Acrobat Reader Fill & Sign

The free Acrobat Reader desktop app has a Fill & Sign tool. Click it, choose the text tool, click on the page and type. It also offers check and cross marks you can drop into boxes. Good for: longer forms. Limits: a large install, and Adobe prompts you toward paid features.

Option 4: Penwise (extension or web app)

Disclosure: we make Penwise.

Penwise can add text anywhere on a page, so it works on flattened and scanned PDFs. It also adds check and cross marks, today's date, and a white-out tool to cover old entries. Items can be dragged, resized and recoloured, and you can undo. Downloads have no watermark and nothing is uploaded, because the PDF stays in your browser.

1. Install Penwise, or try it in your browser with no install.
2. Open your PDF.
3. Pick the text tool, click a blank line and type.
4. Pick the check mark tool and click each box that applies.
5. Use white-out to cover any wrong or old entry, then type over it.
6. Download.

Good for: forms with many boxes and lines. Limits: no OCR, so scanned text is never made editable. The extension needs Chrome; the web app works in other modern browsers, though Pro tools are extension-only.

Tips for a neat result

• Match the font size. Start small. Text sized to the line height looks like part of the form.
• Sit text just above the line, not on it. Zoom in to align it.
• Use check marks for boxes instead of typing letters. They are centred and cleaner.
• Fill the whole form, then zoom out and scan the page for anything crooked.
• Check the result in another viewer before sending it.

Questions

How do I know if a PDF is fillable?

Open it in Chrome or Acrobat Reader and click a blank line. If a field highlights or a text cursor appears, it is fillable. If nothing happens, it is flat. Fillable fields are often highlighted in light blue or grey when you open the file.

Can I fill a scanned PDF?

Yes, by placing text on top of the scan. The scan is a picture, so the page itself is not edited. Add text boxes over the blanks and download a new copy.

Does Penwise turn scanned text into editable text?

No. Penwise has no OCR, so text in a scan stays an image. You can add new text over it, or cover old entries with white-out.

Does white-out remove what is underneath?

No. White-out only paints over it. If the original text is real text in the file, it can still be selected or extracted. For anything sensitive, use true redaction instead.

Related: fill out a PDF form for free · redact a PDF properly