I saw that BTC will have a new hardfork named BTG and I read that we can earn BTG by holding some BTC.
So my question is how its working ? which wallet ? woot ?
It's a good question.
How it works? Bitcoin Gold will be airdropped to anyone owning Bitcoin (private keys) at the specified date and time in November. Only people who own private keys will be able to collect and redeem the Bitcoin Gold airdropped to that private key.
As for which wallet, it depends. Most wallets aren't talking talking about how they'll handle it yet. They'll start making decisions once we get into November. Some wallets will honor Bitcoin Gold, some won't. Exchanges are most likely not to (they have the option since they own the private key for the bitcoin owed to their customer's accounts.) If you have a hardware wallet with private keys, you will be able to claim the Bitcoin Gold...guaranteed.