How to scan a document with your phone
There is a real scanner hidden in apps you already have — and a few small habits that decide whether the result looks scanned or photographed.
On iPhone: it's inside Notes and Files
Apple never shipped a standalone scanner app, which is why so many people install one. It is built into Notes. Open a note, tap the camera button above the keyboard, and choose Scan Documents. Point the phone at the page and it detects the edges and captures automatically; you can drag the corners to correct the crop before saving.
The Files app has the same thing. Tap the three-dot menu in the top corner and choose Scan Documents. This route is often more convenient because it saves straight into a folder as a PDF rather than living inside a note.
In both, the scanner applies perspective correction, boosts contrast, and stacks multiple pages into a single PDF. Tapping the filter icon lets you switch between colour, greyscale and black-and-white — greyscale is usually the right choice for printed text, and it produces a much smaller file than colour.
On Android: Google Drive, or the camera itself
Google Drive has had a scanner for years: open Drive, tap the plus button, choose Scan. Recent versions of Android and Pixel devices also expose a document mode directly in the camera app, and Google Lens will detect a page and offer to save it as a PDF.
Samsung phones do this differently — the stock camera detects a document in frame and shows a Scan button without needing another app at all. If you are unsure what your phone has, point the camera at a page and wait a second; a surprising number of devices offer to scan it unprompted.
The habits that actually decide the quality
Phone scanners are good enough that the software is rarely the limiting factor. Almost every bad scan is bad for one of the same five reasons.
- Shadow across the page. This is the big one. Your own head and shoulders block the room light when you lean over a document. Stand to the side of the light source rather than between it and the page.
- Photographing at an angle. Perspective correction can straighten a moderate angle, but it stretches pixels doing it. Get the phone parallel to the page and the correction has almost nothing to do.
- Colour mode on a black-and-white document. Colour triples the file size and captures paper texture and yellowing you did not want. Greyscale is better for text; pure black-and-white is better still for clean printed pages.
- A patterned surface. Put the page on something plain. Edge detection struggles against a wood grain or a busy tablecloth, and the crop goes wrong.
- Curled paper. A page fresh out of a book or an envelope will curve, and the text near the fold blurs. Flatten it, even just with a hand at the edge of frame.
A scan is still an image
Whatever app you use, understand what you end up with: a PDF containing photographs of pages. There is no text inside it. You cannot search it, select from it, or copy a paragraph out of it, because as far as the file is concerned those are pixels, not words.
That surprises people who assume a PDF implies text. Making a scan searchable takes a second step — optical character recognition — which analyses the image and adds an invisible text layer behind it.
It also explains the file size. A scanned page runs to hundreds of kilobytes where the same page as real text would be a few. If a scanned document is too large to email, compressing it is genuinely effective, because in a scan the images are the entire file.
When the built-in scanner is not enough
The stock apps are fine for a receipt or a signed form. They get awkward when you need to reorder twenty pages, when the automatic contrast has crushed a faint stamp into invisibility, or when the page you are scanning is on a coloured background the filter handles badly.
At that point the useful move is usually to take a plain photograph — no filters, no automatic anything — and do the corner correction and contrast yourself, where you can see what each adjustment costs.
Frequently asked questions
How do I scan a document on an iPhone without an app?
Open Notes, create a note, tap the camera button and choose Scan Documents. Or open Files, tap the three-dot menu and choose Scan Documents — that route saves directly to a folder as a PDF.
How do I scan a document on Android?
Open Google Drive, tap the plus button and choose Scan. Many phones also offer scanning from the camera app or Google Lens when they detect a page in frame — Samsung devices show a Scan button automatically.
Why does my phone scan look grey and blotchy?
Almost always uneven lighting. The automatic contrast adjustment tries to compensate for a shadow across part of the page and overcorrects the rest. Move so your body is not between the light and the document.
Can I search the text in a scan from my phone?
Not by default. A scan is an image of a page with no character data. Running it through optical character recognition adds a searchable text layer without changing how the page looks.
Should I scan in colour or black and white?
Greyscale for most printed documents — it keeps the text crisp at a fraction of the size of colour. Use colour only when the colour carries meaning, such as a highlighted form or a chart.
Why is my scanned PDF so large?
Because it is a set of photographs rather than text. A scanned page is typically hundreds of kilobytes against a few for real text. Compression works well on scans precisely because the images are the whole file.