You may be asked to complete "human verification" surveys to unlock the serial key. These generate revenue for the scammer while you get nothing.
: Most "money adders" require you to pay a "network fee," "tax," or "activation fee" before you can withdraw the fake balance. Even if you pay, you will never receive any funds.
About this app. ... MetaMask is the world's most secure and flexible crypto wallet, trusted by over 100 million users. Trade, buy, Google Play Trust: Crypto & Bitcoin Wallet - Apps on Google Play
Software like "Bitcoin Money Adder v7.1 Ultimate" is a designed to steal your money and infect your computer with malware . There is no legitimate software that can simply "add" Bitcoin to a wallet; Bitcoin must be mined through specialized hardware or purchased on an exchange. How the "Money Adder" Scam Works
If downloaded, delete it and do not open it.