Whether it’s an ID card for an application, a signed contract or a pile of receipts, most offices and websites want paper documents as a PDF. You don’t need a scanner: a phone does the job well. This guide covers scanning straight to PDF, turning photos you already have into a PDF, and fixing the usual problems: sideways pages, extra pages and files that are too big.
The short answer
- Have a phone? Use its built-in document scanner, which saves a PDF directly (steps below).
- Already have photos or scanned images? Combine them with JPG to PDF or PNG to PDF.
- Have several separate PDFs? Join them with Merge PDF.
Scan straight to PDF with your phone
Phone scanners detect the edges of the page, straighten it and boost contrast so it looks like a flatbed scan.
iPhone and iPad
The scanner is built into the Notes and Files apps:
- Open Files, go to a folder, tap the ⋯ menu and choose Scan Documents. (In Notes, tap the camera button in a note and choose Scan Documents.)
- Hold the phone over the page. It captures automatically when the page is steady, or tap the shutter.
- Scan each page, then tap Save. The pages are saved as one PDF.
Android
The Google Drive app includes a document scanner:
- Open Drive, tap + (New) and choose Scan.
- Photograph each page; crop and adjust if needed, then tap + to add more pages.
- Tap Save to store the pages as one PDF.
Many Android phones also have a scanner in the camera or file manager app; the steps are similar.
Scan with a flatbed or document scanner
- Windows: use the Windows Scan app or the scanner maker’s software, and choose PDF as the file type if it’s offered. Otherwise scan to JPG or PNG and combine the images into a PDF.
- Mac: open Image Capture, select the scanner, set Format to PDF, and tick Combine into single document for multi-page scans.
For documents, 300 DPI gives sharp text and is what most offices expect. 200 DPI is often enough for forms and keeps files smaller. Choose grayscale for plain text documents and colour only when colour matters, such as for IDs, stamps and signatures in blue ink.
Already have photos? Turn them into a PDF
If you’ve photographed pages with the normal camera, or your scanner saved images:
- Open JPG to PDF (or PNG to PDF for PNG images).
- Add the images and put them in page order with the arrows.
- Choose A4 or US Letter if the PDF will be printed, or keep Same as each image for on-screen use.
- Select Create PDF and download.
Photos taken sideways are turned upright automatically, and hidden location data in phone photos is removed before it goes into the PDF.
Taking good document photos
- Lay the page flat on a dark, plain surface so the edges stand out.
- Use daylight or bright, even light, and avoid your own shadow over the page.
- Hold the phone parallel to the page, directly above it, to avoid a slanted, trapezoid shape.
- Fill the frame with the page, and check the text is sharp before moving on.
Fixing common problems
| Problem | Fix |
|---|---|
| A page is sideways or upside down | Rotate PDF the affected pages |
| A blank or duplicate page | Remove pages by number |
| Pages in the wrong order | Split the PDF, then merge the parts in the right order |
| Several PDFs that should be one | Merge PDF |
| The PDF is too big to upload or email | Resize the photos to about 2000 pixels on the long side before making the PDF (see below) |
Keeping the PDF small
A scanned PDF stores each page as an image, so size depends on the images. Phone photos are often 3–5 MB each, giving a 20–40 MB PDF for a short document. To keep it small:
- Resize the images to around 2000 pixels on the long side. Text stays perfectly readable.
- Compress them to 75–85% quality.
- Then build the PDF.
That typically brings a page down to 200–500 KB.
Making the text searchable
A scanned PDF is a set of pictures, so you can’t search it or copy its words. Making it searchable requires text recognition (OCR), which reads the letters in the image and adds an invisible text layer. Some phone scanner apps offer this when saving. It’s on xconverter’s roadmap as a browser-based tool. Until then, if you only need the words, Google Drive can open an image or PDF with Google Docs, which runs text recognition and gives you an editable document.
Before you send it
Open the finished PDF and page through it: check every page is present, upright and readable, and that nothing private is visible in the background of a photo. Rename the file to something meaningful, such as passport-copy-2026.pdf, before uploading it.