Although it asks for quite a lot of information, the registration process for FonYou is relatively simple. You only have to enter your ID number as a username and choose a password. This process ensures that it's not possible to create dozens of telephone numbers to use for activities of dubious legality.
Once you have created your additional telephone number you can associate it with your real number to receive all the calls and messages that would normally arrive at the real number direct to your Android phone.
FonYou is an interesting app that helps you to avoid a lot of annoyances when publishing your real phone number. In addition, this app makes it possible, for example, to use Whatsapp without having a SIM card.