As Karfa writes, 2FA via QR codes is totally free of charge.

Ensure you have a legitimate Google Authenticator app and you didn't download something dodgy.
https://apps.apple.com/us/app/google...or/id388497605

There are also third party companies doing the same thing. I personally use Authy.
https://apps.apple.com/us/app/twilio-authy/id494168017

They both work identically: you get shown a QR code, the app reads that (it requires camera access for this), and generates a six digit number NNN NNN. Then, you type that number back to the website to confirm you've done everything correctly, and then in future you just use the app to generate future 6-digit numbers for BA each time. No more QR codes / camera access needed.

Many companies use this method of authentication and they can all be in the same (google or whatever, but stick to the google one if you don't know what you're doing) app.