Go to Settings and choose Privacy & Security, then click the "Enable" button and follow the steps in the pop-up.
Install an authenticator app on your phone. We support Google Authenticator and Authy.
Using the authenticator app, scan the QR code that appears in the pop-up or you can copy the code provided in the pop-up and paste it into your authenticator app.
Next, enter the code provided by your authenticator app.
Click "Enable" and two-factor authentication is now enabled.