To enable two-factor verification follow these steps:
1. Sign in to https://secure.backblaze.com/user_signin.htm with the current Backblaze account email address and password.
2. Choose "My Settings" from the navigation on the left hand side.
3. Select the "Sign In Settings" link on the right hand side of the page.
4. Enter in your current password and phone number and select the "Send Code" button.
5. Check your phone for the text message containing the verification code. Enter the code and select "Verify".