In order to enable two-factor authentication, you must first provide your phone number. See Adding a Phone Number.
Navigate to your Account Settings page.
Click the "Enable two-factor authentication" button in the "Password" section of settings.
If you have not yet added a phone number, you will be prompted to do so.
Click "Send Code" in the "Enable Two-Factor Authentication" dialog to receive a one-time code via text-message.
Enter the code you receive and click "Enable Two-Factor Authentication."
When you login to WayScript, you will now be prompted for a code.
When logging in, you have the option to "Trust this computer." This will prevent Two-Factor Authentication prompts from appearing on that device for up to one month.
Navigate to your Account Settings page.
Click the "Disable two-factor authentication" button in the "Password" section of settings.
Click "Send Code" in the "Disable Two-Factor Authentication" dialog to receive a one-time code via text-message.
Enter the code you receive and click "Disable Two-Factor Authentication."