Go to your Dashboard >> Click on settings >> Click on Security >> Click on Enable 2FA. 

Once the 2FA is enabled, since it is an additional layer of protection beyond your password, every time that you log in, the platform is going to ask you to inform the code showed in the app. 

To get the code, you must go to your app, which you are using for authentication, and check the code generated as it changes frequently.

¹ Make sure you have an authenticator app and that you save the activation barcode somewhere safe in case you need to reset the app for any reason. Besides, try not to use autofill apps, as if it fills a wrong data, your code will not work. Alternatively, if you do, make sure the username and password informed are correct before proceeding.