Cam Scanner is an excellent tool for scanning a variety of documents. It is a PDF document scanner app that can turn your phone into a scanner.
Demo: https://codecanyon.net/item/cam-scanner-android-app-with-admob-ads/32839108
Android Studio Project Scan documents, photos, receipts, reports, or just about anything Adjust color and brightness of image, Convert images to PDF.
Demo: https://codecanyon.net/item/queen-scanner/23310020