The article is going to describe which settings you need to archive Gmail directly in Mail Archiver.
First you need to activate 2-Step verification for your Google account.
Then you need to create an app-specific password for the same Google account.
In Setup -> Accounts click on the plus button to add a new account. Select Gmail with App Specific Password:
Enter your Gmail address and the app-specific password:
If the password is correct then you are done:
You can now add your Gmail account to a plan.
Updated 11-May-2023 with new screenshots.
Updated 16-May-2022 with new screenshots.
Updated 01-Apr-2021 with new screenshots.