In your profile settings in the app, you can easily change the notification settings. Open the app and log in if necessary. Then switch to the “Profile” tab.
You can open “Edit profile” via the menu at the top right or on the left-hand side of the screen.
Once you have reached the profile editing page, scroll down and make sure that the e-mail notifications are not checked. At the end, please do not forget to click on Save. Please note that important e-mails, e.g. when using the forgotten password function or to prove that certificates have been obtained, cannot be switched off.