Two-Factor authentication (2FA) is essential to web security because it immediately neutralizes the risks associated with compromised passwords. Its a cost-effective measure that protects against key threat vectors (and it’s fairly simple to roll out). 2FA also actively involves users in the process of remaining secure, and creates an environment where users are knowledgeable participants in their own digital safety. Authenticator apps such as Duo Mobile use internet connectivity to deliver login approval requests, which is more secure than using phone lines.”]
Source: https://duo.com/blog/two-factor-authentication-the-basics