Having been involved in music in one form or another most of my life, I was really excited when tablets came into widespread usage and I finally had a really mobile and low profile way to handle sheet music! As a piano player (or any other musician) it can get cumbersome to lug around huge books and binders filled with music. Below are my picks for music notation apps. There are quite a few of them out there, and it could be that these don't fit your needs, but it's a good place to start!
I've used this app for about as long as it's been on the market. This app is great for organizing pdf and image files. You can make notations, put together set lists, connect your bluetooth pedal and best of all, the developer and community of users are very supportive. If you're an iOS user, you're out of luck with this one since it's Android only. I'm sure there's something similar for iOS.
A great way to organize all those uke club books in pdf that you collect!
When I started to play ukulele and found that beside pdfs there was this file type called "chordpro" (or sometimes .pro or .chopro) I started to look for an app that would allow displaying, transposing, creating and editing of these text files. Songbook does this so well! You can also create set lists, add alternative chord fingerings, transpose on the fly and engage automatic scrolling. If you have a Dropbox
account you can also sync your tunes across devices - also cool. Songbook is available for Android, iOS and Windows.
I probably use this one less often than the others above, but it's a great app for online searching for a specific tune or by band name. You can also save files in chordpro format and transpose. Don't let the "guitar" in the name worry you ... there's an option to show uke chords too! Available for Android, iOS and Windows.