This app was mentioned in 1 comment, with an average of 1.00 upvote
Personally I've used Chess.com for years, mostly because I've liked their tactics, but it seems a great deal of the chess community prefers Lichess. Both are free, I've only played on Lichess a couple of times and it seems like a pretty nice app, although I don't necessarily see an advantage or disadvantage to it. You'll need to create an account on either, but again, both are free.
I don't like Chess.com for learning initially and I didn't see that option on Lichess, so I took a quick browse through the app store. Coach Jay's Chess Academy is a little childish, but I like it because it's a little more interactive. If you don't like it though, I've included an alternative app to learn on, Chess Guide. This is more of a block of text. You can skip learning Chess history, it doesn't really matter. Don't let the blocks of text discourage you, it really is simple and you could easily master the basics in an afternoon or two if you persevere. I might also suggest youtube for learning the basics.
Once you have the basics down, I would suggest downloading a chess puzzle/tactics app. This will help you get familiar with the different ways you can use your pieces. I'm afraid I might not be able to suggest a proper chess puzzle app for this because the right app to use will depend on your ability, so you'll have to feel it out a little. The first few games you play online you will be paired against tough opponents. It will choose better opponents for you the more games you play. If you get frustrated, both apps have the option to play against a computer which you may set to an easy level.
Learning:
Coach Jay's Chess Academy: https://play.google.com/store/apps/details?id=com.ghostmaninc.coachjayschessacademyandroid
Chess Guide: https://play.google.com/store/apps/details?id=com.raymongulati.chessmanual
Playing:
Lichess: https://play.google.com/store/apps/details?id=org.lichess.mobileapp
Chess.com: https://play.google.com/store/apps/details?id=com.chess
If you ever need help, r/chess will be able to provide assistance