What is the 2FA?
Two-factor authentication (2FA) gives you additional security in the login process. It requires the common login process, taking your email address and password, and additionally provides a verification code for a second device, usually a mobile phone.

Which options do I have to activate my 2FA?
Via SMS and Google Authenticator. Google Authenticator can be downloaded from App Store and Play Store.

Is it mandatory to activate the 2FA?
It is not mandatory, but it is highly recommended, to avoid any hacking action vs your account.