You can add or modify the phone number used for authentication and turn authentication off under your account information. 

Add a phone number

1. Tap the user icon in the upper right corner of the screen and select Password / Accounts.
   
   
2. Click on the Add button below Phone Number to add a mobile phone number to receive a code via text message.
   
   
3. Enter your Phone Number and click on Submit.
   
   
4. A text with a code will be sent to your phone number. Enter the Code to verify your phone number and then click on Submit.
   
   

Modify your phone number

1. On the User Settings page, click on Change below Phone Number.
   
   
2. Enter the new phone number you want to use and click on Submit.
3. A text with a code will be sent to the new phone number. Enter the Code to verify your phone number and then click on Submit.

Disable Two-Factor Authentication

You can turn Two-Factor Authentication off if you are unable to access your email and phone number. 

1. On the User Settings page, click on Disable under Two-Factor Authentication.
   
   
2. Click on Enable to turn Two-Factor Authentication on.