You will receive an email by default when a new document has been uploaded, for example. 
This can be disabled via the settings and is then immediately disabled for all emails of any type (updates, documents, expenses, etc.). This cannot be done for individual items.

How do you do this?

Click on the “Profiel” tile and there on the initials of your name and then choose "Instellingen":

Under "Notificaties" you can choose whether or not you want to receive notifications by clicking on the slider.

Is this slider and the text in blue? Then you will receive the notifications via email.
Is this slider and the text in grey? Then you will not receive the notifications via email.