Google

https://accounts.google.com
Recommended Configuration SMS; Authenticator; U2F
Alternate Configuration 1 Authenticator
Alternate Configuration 2 Proprietary; U2F
Alternate Configuration 3 SMS; U2F; Proprietary
Account/Password Recovery PR email; PR SMS only if SMS 2FA is not enabled; PR manual review
Remarks
img
2fa_options.png
img
2fa_signup_step0.png
img
2fa_signup_step1.png
img
2fa_signup_step2.png
img
pr_2fa.PNG
img
pr_step0.png
img
pr_step1.png
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pr_step2.png
img
pr_step3.PNG