Go to the Notifications menu.

Uncheck "Form submitted if you don't want to receive notifications when form submitted.

In some cases you don't want to receive email notification about added records from "Records" page.

You can turn them off by unchecking "Form submitted from 'Records' page" option.

Once unchecked you'll stop receiving emails while working inside QuintaDB. But you'll still receive email if your form widget were submitted, if the first option is turn on.