How can I activated the two-factor authenticator if I don't have any QR Code Scan?

I don't think you understand how it works.
The 2FA is a 6 digit code that comes from a third party app (whether you wanna have it on phone, pc or browser) and that code you will put in the login page on lichess, after your password.
In order to setup your 2fa app you need to make firstly a personal account and then you have to add the online account (in this case lichess) for which you wanna add the 2fa.
Following the guide I posted above, you will be asked to scan the QR code that you find on lichess.org/account/twofactor or if you can't, manually insert the secret code in the 2fa app. Once the registration is complete you will be able to request the 6 digit code anytime.

@Deadban said in #11:
> I don't think you understand how it works.
> The 2FA is a 6 digit code that comes from a third party app (whether you wanna have it on phone, pc or browser) and that code you will put in the login page on lichess, after your password.
> In order to setup your 2fa app you need to make firstly a personal account and then you have to add the online account (in this case lichess) for which you wanna add the 2fa.
> Following the guide I posted above, you will be asked to scan the QR code that you find on lichess.org/account/twofactor or if you can't, manually insert the secret code in the 2fa app. Once the registration is complete you will be able to request the 6 digit code anytime.
Ok.
but where can i get that?
an app?

Yeah an app that provides that service, there are many.