There is something about writing in a notebook that helps make a better memory of an idea or concept. That is why I use a physical notebook in my daily life and encourage my students to use physical notebooks too. I also encourage digitizing those notes with a mobile app.
There are lots of apps that can digitize physical notes. The following are the three that I actively use and recommend.
Office Lens & OneNote
Office Lens is Microsoft’s free app (Android and iOS versions available) that anyone can use to take a picture of physical notes and have the handwriting in those notes turned into text that can then be used in Word and other Microsoft products.
When it comes to digital notebook tools Microsoft is far ahead of what Google offers (I say that as someone who has been a Google Certified Teacher for more than a decade). Case in point, OneNote includes a feature that converts handwriting into text. You can hand-write notes in the web, desktop, or mobile versions of OneNote and have those notes turned into text. You can re-arrange handwritten notes within OneNote.
Google Drive & Docs
All of my students have G Suite for Edu accounts so I do encourage them to use the Google Drive mobile app to save pictures of their physical notes. When they look at those pictures in Google Drive in their web browsers they can right-click on the image to open it as a Google Doc. When that option is used the image will appear in a Google Doc and below the original image will be text based on the handwriting in the image. It should be noted that students who have sloppy handwriting will have mixed results with this method.
The Post-it app is made by the same company that makes the little sticky notes that litter my desk. The app (available for Android and iOS) lets you snap a picture of a collection of sticky notes that you want to digitize. After snapping the picture you’ll be able to sort and group the digitized version of your sticky notes. You can export your digitized stickies and groups of stickies as PDF, PowerPoint, and Excel files. Watch the video below to see how the Post-it app works.