App Passwords for Google account are auto-generated 16-digit passcodes which can be used for signing into apps which don’t support the Sign-in with Google option or a 2-Step Verification.
In most cases, using them isn’t necessary or recommended but they still can be used for legacy apps if required. These can also be used if signing in to older apps is blocked using the regular Google account sign-in option.
Here is how to configure App Passwords:
Sign in to your Google Account page and from the Security section check if the 2-Step Verification is enabled for your account there, as it is required for using App Passwords. After it is enabled, there would be an option of App Passwords below it. Click on that.
You can then choose either the App or the Device option for generating the password.
There will already be some default apps listed for that, but you can use a custom app name too.
After selecting that, click on GENERATE. This will generate a random 16-digit passcode. It does not need to be remembered and only requires to be entered once for the app or the device for which it was generated.
Click on DONE.
From now on, you would be automatically signed in to your Google account whenever using these apps and devices because of the App Password.
To remove generated App Passwords, click on the delete icon next to them.
Again, it is not preferred whenever there is an option of Sign-in with Google, but it can be useful for older or legacy apps and devices.
Also, it is a good idea to periodically review the security settings for your Google account.
All done.