One of many easier ways of buying and having usable Bitcoin:

1. Download, install, and open CashApp on your phone.
2. Make an acct if needed, log in. Tie a debit card to it.
3. Swipe or navigate to left side of the main app, you'll see Bitcoin. It's under the little house looking icon section.
4. Tap Bitcoin, then tap Buy. It has some preset suggestions, but buy as much or as little as you need.
5. Complete the order. That BTC is immediately ready for use or transfer.

DO NOT USE CASHAPP AS YOUR SENDING WALLET FOR YOUR ONLINE ACTIVITIES. You can imagine it'd be way easier to tie you to something if your BTC wallet and digital market/bank were the same app.

6. Pick another BTC wallet. Any, I use Cake Wallet since Samourai died and then Green failed me one too many times and I lost BTC. Cake is just the wallet du jour for me, but use anything. Non-custodial wallets are best. Do more research on that and all this, quite frankly.

7. Make a new, regular non-special no frills wallet in the new app, and copy the BTC address it contains to receive funds. Usually all default options are fine when setting one up. Unless you want to add 2FA, which is always a good idea, but optional.

7. Once the new wallet is installed, go through CashApp and where it shows Buy, it also has a up/down arrow button. Tap that, then tap Send.

8. Enter the amount of BTC you wish to transfer to the new wallet, and then paste the address you copied from your other, new wallet. That will let CashApp find your new wallet, send the funds to the Blockchain, and depending on what priority you put on the transfer it could take 2-24 hours. Roughly. It's usually fairly quick.

That's one guy's quick-n-dirty way of buying and using BTC (or other coins) online.