Where can I manage all the notifications?

Engage Process automatically sends notification emails to the parties involved when

• a diagram is shared,
• a diagram is submitted for publication,
• a process is submitted for approval or its approval state is changed,
• a comment is created or its state is changed,
• a Teamboard work item or a task is assigned to a user.

Open the Admin center tool by pressing the application launcher button on the top-right of the window and then select Admin Center (you can login directly to it using the link https://admincenter.engageprocess.com). Select on the left of the screen the Notifications tab.

By checking off a given box you will automatically block the corresponding type of notifications for all users in the organization. 

You cannot block the notifications here that are sent to publishers when a diagram is submitted for publication. Each publisher can do this for himself using Engage Process Publisher
Each viewer can also block the sharing notifications individually by checking off the Receive email when a diagram was shared with you checkbox in the Engage Process Viewer.