One Note mostly. I like Samsung Notes for taking the written notes, convert them to text, and paste in One Note (mostly work purposes). I know, seems like an awful lot of work but when you use screen off memos a lot, it works really nice.
Google Keep
One note
Evernote - if you really want to go across devices and on the computer
Squid (formerly Papyrus) - Very similar to the other note apps but I used it on my old LG G Stylo since I had no access to Samsung Notes.