To scan documents, open WhatsApp on your iPhone, go to the chat, click the plus (+) icon, select Document, and tap Scan Document. You can add up to 24 pages into a single document.

You can save time and energy if you scan and save a document directly to OneDrive. OneDrive document scanning feature explained.

If you need a digital copy of your license or some other document, there's no need to buy a scanner. Use your smartphone or webcam instead.