How to Scan Documents to PDF on Android for Free

Prepare the document before you capture anything

A good scan starts before the camera opens. Flatten the page as much as you can — unfold corners, smooth out creases, and take pages out of binders when they curve near the spine. Put the paper on a surface that contrasts with it: a white page on a dark tabletop gives corner detection clean edges to find. Remove other papers, books, and anything with strong edges from the frame, because the detector may grab the wrong rectangle.

Lighting matters more than camera quality. Even, diffuse light beats a bright spot: daylight from a window or a well-lit room works, while a single lamp pointed at the paper creates glare and shadows. Avoid casting your own shadow over the page — hold the phone so your body is not between the light and the document.

Capture: framing, corners, and a steady hand

Open the scanner in Offline Scan & Photo Toolkit and point the rear camera at the page. Corner detection runs live on the camera preview, so you will see an outline settle onto the document's edges before you capture. Hold the phone as straight-on as you can — the app's perspective correction flattens the page, but a flatter start keeps details sharper. When the outline matches the edges, capture the frame.

After capture, a crop screen shows four draggable corner handles. Drag any corner to fine-tune the outline. This is the fix for busy backgrounds, curved pages, and documents where the detector caught the wrong rectangle. When you are happy with the crop, move on to enhancement.

Enhancement: pick the profile that fits the document

The enhancement step is where a phone photo of paper becomes a document. The free profiles cover the common cases: Original keeps the capture as it is; Document brightens the page and boosts contrast for cleaner text; High Contrast pushes further for faded or low-contrast pages; and Black & White gives text-heavy pages the classic clean scanned look. Preview each profile before you commit. A small set of advanced enhancement profiles is premium.

• Faded receipt or old letter? Try High Contrast or Black & White.
• Colorful form or a photo on the page? Original or Document keeps the color.
• Text with a gray cast? Black & White removes the gray.

From scan to PDF

Your scan is saved to the app's local library. To get a PDF, open the PDF tools and create a PDF from your scans. You pick the images, the page size, fit, margins, and quality, and the app builds the PDF on your device. For a multi-page document, add all of the scans to one PDF in the order you want them — creating a PDF from several images is free.

The finished PDF opens in the built-in viewer so you can check every page before you send it. Sharing happens through the apps you already use — attach it to an email, send it in a chat app, or upload it wherever you need it. If you need to combine separate PDFs into one file, split a PDF, or reorder pages of an existing PDF, those are the premium tools.

Common scanning mistakes and how to fix them

• Blurry text: you moved during capture. Brace your elbows on the table, rest the phone on the page if light allows, and recapture.
• A dark gradient or shadow across the page: uneven light. Move near a window or add a second light source from the opposite side.
• The detector grabbed the wrong rectangle: too many edges in the frame. Clear the background, then drag the corner handles on the crop screen to correct it.
• Warped or stretched text: you captured from a sharp angle. Hold the phone more straight-on; perspective correction fixes the rest.
• Page looks gray instead of white: try the Document or High Contrast profile, or Black & White for text-only pages.

A practical workflow for receipts, forms, and notes

1. Flatten the paper and set it on a contrasting, uncluttered surface in even light.
2. Capture with the scanner, checking that the corner outline matches the page.
3. Fix the crop with the corner handles if the detector was off.
4. Apply the enhancement profile that makes the page easiest to read.
5. Save the scan, then create a PDF from your scans in the PDF tools — adding every page of the document to one PDF.
6. Check the result in the viewer, then share the PDF.

What happens to your scans

Scans and PDFs stay in the app's local storage, with a browsable history you can search by name, filter, and mark as favorites. Deleted items go to a trash with a 30-day recycle bin, so you can restore something you deleted by mistake. Processing runs on your device with models bundled in the app, and no account is required — documents aren't uploaded for cloud processing. Read how the app handles your documents for the full picture.

Frequently asked questions