Fret no more. With a simple scanner app in your smartphone, you can save each and every important receipt the moment you have it. How about that: a filing system on the go! I use an app called "ClearScanner". Apart from being able to crop the image, rotate, and change the colour temperature, etc, I can also scan multiple pages into one pdf file. Plus, I can save it directly to a pre-assigned folder in my Google Drive. Of course, I can also share it in multiple ways, such as email, Whatsapp, etc.
The following images are screenshots from my phone:
The first one is the app. The second one shows two files I have scanned (one single page and one two-page document, as indicated).