If I transfer BTC to a friend/family, they now know my wallet address, correct? Does this mean they can see all the transactions I have done from that wallet? It seems like wallet information is public except for identity, but that would be forfeited once I make a transfer, right?
Of course as the blockchain itself of BTC is a distributed public ledger that is tamper-proof that can be seen by anyone, especially your close family members and friends once you have sent them some BTC or any other cryptocurrency. They can check the history of your transactions from the very beginning. That’s what crypto transactions are.
Unless you don’t want them to see your main wallet, you can simply create another Bitcoin wallet and deposit some BTC. But make sure the sender is not from your main wallet, but from an exchange. Or much better if you knew someone who do P2P transactions.