Doc Scanner is the most simplest app to scan your document with enhanced quality or generating PDFs of receipts, notes, or anything else as simple as a single tap. The app automatically lines up, isolates, and enhances the final scan, bringing out text and making it more prominent in the final image and then converting the whole thing to PDF and keeping it in your local device so you can email or share it later.
The app also gives you some basic editing tools, like auto cropping and archiving. The app is completely free, but a $2.99 upgrade to the premium version (via in-app purchase) strips out the ads, adds features like unlimited Scan, Enhance Document, Magic color and the option to save to cloud storage services like Dropbox, Google Drive.
Doc scanner also facilitates you with QR/ Barcode scanning. It helps you scan QR Code and Barcode very easily with a single app.