There are robust services for document signing (Docusign, and many others) but what about the random PDF that you receive that just needs your signature?
If you're saving them, printing out, then signing and scanning or photographing them, there is a much easier way: use the built-in Preview app.
Apple includes instructions here: https://support.apple.com/guide/preview/fill-out-and-sign-pdf-forms-prvw35725/mac
It's unbelievably easy to use once you get your signature in, and getting that in is SUPER easy with nearly all modern Macs. Wouldn't it be simplest if they just let you sign a white piece of paper and then hold it up to the camera? Yes, that's what Apple thought, too. Once you add your signature(s) to the Preview app, you can just add signatures (and other text, shapes, arrows, etc) to PDF's and then turn them around and email them back to whomever needs the approval. If you're having difficulty getting this to work, let us know. You'll likely use this feature every month or even every week if you do a lot of signing. Printers are becoming more passé and printer ink isn't getting any cheaper.