Over several years, I have tried various apps to turn written pages into pdfs that I can then easily email or save to the Google Drive. I settled on using the camera on my iPhone, then a special ‘pinch’ that prints selected photos to a pdf, that I can then share as needed.
Over Christmas, my son pointed me to an app that he uses at University, which is now my default. The app is Adobe Scan, which is free to download and very intuitive. If you point the camera at a sheet of paper, it looks for a document and then shows the area it judges you want. You can move some markers in each corner to select the area you want, and then it captures the image, adjusting the lighting as necessary. Again, you can move the markers around the image to select exactly the parts you want.
You can add additional pages as required and there are useful tools such as cleaning up images, adding pages, reordering pages, and cropping images to allow you to create the exact document you want.
Finally, you can name the document, create a pdf and then share by emailing, save directly to the Google Drive, print or create a shareable link. The output is the highest quality pdfs that I have captured so far, whilst the app is very easy to use, and offers much more than I am currently using.