Start from your "Personal Dashboard" and click on your profile picture. Choose "MY ACCOUNT".
You can find "Settings" directly under your personal information. Click the "Off" button turn off the mail notifications. Reactivate them by clicking on the "On" button if you change your mind!
Be sure to save the settings by clicking on "Update Settings".
You'll no longer receive mail but you'll still be notified about recent activities when logging into your account.
If you'd like to know more about the notifications, please read the article "Booking notifications".