You download or screenshot that QR Code while subscribing for 2fa with GA. Also keep the subscription key; & save both in a password database seperate from your

You download or screenshot that QR Code while subscribing for 2fa with GA. Also keep the subscription key; & save both in a password database seperate from your usual password database. 2fa on phone totp is safe; SMS 2fa is less safe, prone to easy attacks. For phone somebody need to come n physically snatch your phone, get app lock password from you. For SMS, in few countries, not in India(in India either you need to prove that you own that existing SIM by getting a code there, or by seeing a customer service desk) a bit of social engineering & few answers from Facebook profile enables hackers to get a copy of SIM.