You can create and manage app passwords in “Settings” via “Password and security”.
These passwords typically only need to be entered once in the respective application. You will not be prompted to enter it again each time you open the application. If a device is lost, stolen or is otherwise compromised, you can simply delete an app password in the settings of your Posteo account. By doing so, you can intentionally prevent any potential unauthorized access without needing to change your email account’s password and then update it in multiple programs as the case may be.

You can also complement app passwords with two-factor authentication: This secures access via the Posteo website and our web app with an additional one-time password. Two-factor authentication also protects access to your Posteo account settings as these are only available via the webmail interface.
Do you only want email clients and devices to be able to access your emails if an app password is used? If so, then activate additional email account protection. This blocks external applications from accessing emails using the Posteo password.

Application passwords can also be used in combination with crypto mail storage, a feature that encrypts all your emails with your passwords.

App passwords are an optional feature for external applications – such as email clients and email apps.
If you exclusively use Posteo via our web login or the Posteo web app, this feature has no relevance for you. Tip: For optimal protection, activate two-factor authentication and additional email account protection.

You can learn how to use app passwords in our help section: https://posteo.de/en/help/app-passwords

Best regards,
Your Posteo Team