What You Need

•A phone or computer with a camera — Any modern smartphone camera works. Laptop webcams work too, but phone cameras produce better results.
•A web browser — Chrome, Safari, Firefox, or Edge. No app to download.
•Decent lighting — Natural light or overhead lighting. Avoid casting shadows on the document.

How to Scan a Document to PDF

1
Open MiOffice Document Scanner
Go to the Document Scanner in your browser. On mobile, your phone's camera will activate. On desktop, you can upload a photo of the document.
2
Position and Capture
Hold your phone directly above the document, keeping it as parallel as possible. The scanner will detect the document edges automatically and highlight them with a blue overlay. Tap the capture button when the edges look right.
3
Review and Adjust
After capture, the scanner applies perspective correction to straighten the document. You can adjust the crop corners if needed. Choose an enhancement mode: Auto, Grayscale, Black and White, Color, or Whiteboard.
4
Add More Pages (Optional)
Scanning a multi-page document? Tap "Add Page" to capture additional pages. All pages will be combined into a single PDF.
5
Download Your PDF
Tap Download to save your scanned PDF. The file is generated entirely on your device and never uploaded anywhere.

Tips for the Best Scan Quality

Do This

+Use even, diffused lighting from above
+Place the document on a contrasting surface (dark table for white paper)
+Hold the camera directly overhead, not at an angle
+Flatten the document — press out folds and curls
+Clean your camera lens before scanning

Avoid This

-Scanning near a window with direct sunlight (causes glare)
-Placing documents on a same-color surface (white on white)
-Capturing at extreme angles (perspective correction has limits)
-Moving while capturing (causes motion blur)
-Scanning in low light (introduces noise and reduces sharpness)

Enhancement Modes Explained

Auto (Recommended)

Automatically adjusts contrast, brightness, and sharpness. Best for most documents.

Grayscale

Converts to grayscale with optimized contrast. Good for printed text documents.

Black and White

Pure black and white with adaptive thresholding. Smallest file size, ideal for text-only documents and forms.

Tip: Use "Color" mode for documents with colored charts, logos, or photographs. Use "Whiteboard" mode specifically for whiteboard captures — it removes the board background and boosts marker contrast.

Phone vs. Computer: Which Is Better?

Aspect	Phone Camera	Webcam / Upload
Image quality	Excellent (12MP+)	Good (varies)
Convenience	Point and shoot	Requires prior photo
Multi-page speed	Fast (scan in sequence)	Slower (upload each)
Best for	On-the-go scanning	Digitizing existing photos

Common Use Cases

•Contracts and agreements — Scan signed documents to send as email attachments.
•Tax documents — Digitize W-2s, 1099s, and receipts before filing season.
•Medical records — Keep digital copies of prescriptions, lab results, and insurance forms.
•Student notes — Scan lecture notes and handouts into organized PDF notebooks.
•Business cards — Scan and archive contact information from networking events.

Specialized Scanners for Specific Documents

While the general Document Scanner handles most cases, MiOffice also has purpose-built scanners with optimized settings:

Receipt Scanner

Optimized for small thermal receipts

ID Card Scanner

Passport and ID sizing, never uploaded

Book Scanner

Handles curved pages and book spines

Batch Scanner

Scan 20+ pages into a single PDF

FAQs

Is my scanned document uploaded to a server?

Yes, private & secure. Processing happens in your browser in your browser. When you close the tab, the data is gone.

Can I scan to formats other than PDF?

The scanner outputs PDF by default, which is the standard for scanned documents. If you need JPEG or PNG, use the Photo to PDF tool in reverse or save the enhanced image before PDF conversion.

What is the maximum number of pages I can scan?

There is no hard limit. The Batch Scanner supports scanning dozens of pages into a single PDF. Performance depends on your device's available memory.

Does it work offline?

After your first visit, the scanner's core processing (edge detection, perspective correction, PDF assembly) is cached in your browser. Camera capture requires an initial page load but works without continuous internet.

How to Scan Documents to PDF (Phone or Computer)

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