Not sure which specific apps that you are referring to but as far as I am concerned, they are probably not real. They are more like a bitcoin faucet that dispense the user with a little amount of satoshis overtime. There isn’t any real bitcoin mining activity going on in the background. The apps entice you to spend more time in the apps so that they will be able to sell/ earn from the ads. A fraction of their earnings goes to you. However, I bet the actual profits are negligible and not worth your time. Even if there is some real mining activity going on, the processing power of a phone or even a pc is too low for bitcoin mining nowadays. The mining activity will cost your more electricity cost + wear your device out faster than you will be making.
If you really want to get started on bitcoin mining, the following article might help. I would actually recommend you to check out mining other crypcurrency with high upside potential as bitcoin mining nowadays are getting more and more competitive to be actually profitable in the long run unless you are betting on a tremendous rise in bitcoin’s value in the near future. Hope that this helps.
Bitcoin Mining: A Complete Overview for Beginners