The out-of-box timesheet notifications are sent with email id of who submits or rejects the timesheets.
For example, if 'resource_A' submits timesheets, then notification email to approver is sent from 'resource_A's email id.
Is it possible to change this sender's email address to a generic email address?
Clarity PPM 15.x, 16.x
There is not an option to change this on the notification templates:
Configure Notifications and Notification Templates
It is not possible to modify it either at CSA/NSA level.
This has been asked a few times in the communities already:
CA PPM Default Sender Name & Address Issue
Specify Display Name shown as a sender of Email notification
To bring this as an idea/enhancement to Product management, follow the procedure: