Actually only SYSADMIN user can view other users notifications, if a requirement comes to enable everyone/certain group of people to view everyones notifications.
Login as SYSADMIN User
System Administrator - Workflow : Administrator Workflow - Administration.
-> In the admin page you will see this message “Set * to grant admin privilege to all users”
-> Put * in the text box next to “Workflow System Administrator” and click Apply.
Just in case if stil issue exist, we can also use below sql from APPS user to update the workflow administrator.
update wf_resources set text='*'
Happy EBS Learning !!