Not every wallet will allow you to sell your bitcoins directly in a mobile app. Take a look at Blockchain.info or Coinbase. I don't remember if they force their users to pass through KYC but using one of these services will be much easier for you than looking for a Bitcoin ATM in your area or creating an account on any other exchange. They are not a good place to store bitcoins long-term.

Here you can learn how to sell your BTC on Blockchain.info.