If you don't want to mine bitcoin, it can be bought using a crypto currency exchange.Most people will not be able to purchase an entire BTC because of it's price, but you can buy portions of btc on these exchanges of fiat currency like U.S dollars.For example you can purchase bitcoin on coinbase by creating an account and funding it, you can funds your account using your bank account, credits card, or debit card.
I would advise you to use Coinbase and other centralized exchanges that ask for KYC only as a last resort if there is no other way to buy Bitcoin. If you want to put some effort into it and avoid giving your documents, best is to buy Bitcoin either directly peer to peer from someone you know, or maybe using bitcoin ATM. And even if you buy from centralize exchange, withdraw it immediately in your own wallet and dont store it there as you never know what will happen.
Another good option is fully decentralized exchange Bisq but only after you already have some bitcoin as it asks you to put safety deposit before you can buy or sell.