I see a lot of alternatives being discussed here so I’ll just throw one more on the pile for Mac users: Devonthink.
It organizes and centralizes a bunch of stuff for me. Has tagging, folders, a bunch of handy metadata and even tries to automatically sort/file things. It allows separate databases for work, personal or projects. Syncs/backs up via popular cloud providers - even multiple if you want redundancy. Just about the only thing I wish it did a better job of is scanning to PDF with a phone camera.