Google Drive is one such app that’s has integrated document-scanning and OCR capabilities. Snap a photo of a document and a PDF copy of the document will be saved to Google Drive. It will also use the power of Google’s servers to perform OCR on the documents, making it searchable in your Drive.
To do this, open the Drive app on your phone, open its menu, and tap Add New. Tap the Scan option in the list to scan and upload a document. Note that you could also add the Drive widget to your home screen and tap the camera icon on it to quickly open the Scan interface — this is useful if you frequently want to scan documents.