Sometimes you wanted to scan an important document, but you are left with no scanner. If you own an iPhone or iPad, the best way to save documents is by using the iPad as a scanner. The iPhone has a very good camera and this can be used to scan documents, save it as PDF and then upload it to cloud or access it locally.

1. CamScanner Free

Enhanced Image Processing: Scan anytime and anywhere. All paper documents, receipts, notes, invoices, whiteboard discussions can be scanned and processed automatically. Enhanced image processing technology ensures images more clear and readable. Multiple edits are supported.

Smart Management：Group management, Sort by Date or Title, and Tag or Thumbnail views, manage all scanned documents smartly. 

Easy Share & Cloud Storage: Upload the scanned files to cloud storages, fax or back up them in handy, share via iTunes or Wi-Fi.

2. Genius Scan

 Genius Scan turns your iPhone into a pocket scanner. It enables you to quickly scan documents on the go and email the scans as JPEG or PDF. 

The Genius Scan scanner technology includes smart page detection, perspective correction, image post-processing. It allows you to build PDF documents with multiple scans.

3. Office Drop

 The best way to scan, search, sync and store your paper is now available on your iPhone and iPad. OfficeDrops is a free, searchable cloud storage service that lets you scan paper, text search paper & digital files, organize everything and share files – right from your mobile device, the web or from your Windows PC (Mac coming soon).

4. DocScan

DocScan lets you instantly scan multi-pages document and send out when there is no scanner nearby. By having it, you can scan not only documents in sight, but also whiteboards, receipts, business cards, posters, coupons, books …etc.

It can fast auto-detect document edges from a picture, correct perspective distortion, remove shadows and brighten it up to produce a clear and sharp document, especially useful in a Low-Light environment. 
You can draw lines or annotate on the scanned image before saving it as a PDF document. 

In addition, DocScan has a built-in PDF viewer for previewing scanned documents and browsing pages in detail. You can easily swipe over a page to delete it or press Edit button to reorder pages in list. Each PDF file can be accessed directly from iTunes or you can email out as a PDF, JPEGs or a zip file.

Enjoy!