A Project Administrator is a member with the added privilege to administer or manage a project.
When you have many users and projects in Backlog, this increases the difficulty for the Administrators to manage members and who is involved in which projects. In situations like this, the administrator can delegate a member to manage the project by assigning them as a Project Administrator.
Note: Guests cannot be assigned as Project Administrators.
Project Admins can access the full project settings to manage the project, as well as add/remove project members:
For members, they can only access the basic project settings: Issue Types, Category, Version/Milestone:
You can add users to the organization as a member and assign them the Project Administrator privilege, so that under their own initiative, they can manage their respective projects and project members.
What you want to achieve:
To delegate project management responsibilities to other users — e.g. project or department managers — within their respective projects.
What you can do:
First, create a project or use an existing project. Then, add a member and assign them as the project administrator. They can then continue to add/remove other project members and adjust the project settings accordingly to fit the project’s needs.
Note: Project administrators can only add existing users in the space/organization to projects. For adding new users to the organization, the project administrator needs to have inviting privileges. This can be granted to project administrators and members under Organization Settings.
Useful links for more details: