As per our documentation here, a user with Project Administrator permission can edit the Notification Scheme for the project. But this does not happen if the user does not belong to the jira-administrators group.
- Create a user with membership "jira-users"
- Add the role "Administrator" to the user.
- Add "Administrator" role to the "Administer Project" permission.
This would make this user an Administrator for the project.
Now, go to the Project->Notification click More. You will not see the Actions gear box on the screen.
This is reproducible with most versions of Jira. So I believe there is something wrong with the documentation and it needs to be updated.