Push a button inside this app to start mining Electroneum on your phone. It doesn't use any of your phone's resources and keeps on mining continuously for a week whether the phone is on or off. It's as simple as that.
The ETN currency can easily be sent to an exchange and traded for Bitcoin or Ethereum, the minimum withdrawal is only 100 ETN, which is currently at the time of writing this about $0.30.
Android: https://play.google.com/store/apps/details?id=com.electroneum.mobile
iOS: https://apps.apple.com/gb/app/electroneum/id1270774992
To earn 1% more while mining, use the referral code DC4EFA or scan the QR code below.
Refer your friends to the app using your own unique code to earn 5% of what they mine.
Another similar app is Pi, a new currency being developed by a group of Stanford PhDs.
Still in the testnet phase, the coins you mine can't be traded until the mainnet goes live and it's listed on exchanges, but if speculating on the success of this coin interests you, you can join the beta to earn Pi and help grow the network.
To join Pi, follow this link https://minepi.com/singingdan and use my username singingdan as your invitation code.
If you know any other apps for mining cryptocurrency, feel free to leave a link the comments.
Have a great day!