If you enable the option Continuous saving of email messages then it means that a new email message matching the label or the search filter will be automatically exported and saved into OneDrive folder.

For example, if you setup automatical export of the label Support to Drive folder called Support, then as soon as you add email to the label Leads the email will be added into Drive Support folder.

The continuous job can be paused or aborted via the dashboard.

automatically save emails