In Project settings you can manage some of projects attributes to fit them to your preference. Change preferences for requests within project, manage project's members and permissions.
To access project settings open the project and in top right corner of project header click on project actions button 1 and then select project settings option 2 from the popup.
Request settings
Manage request related settings such as request key prefix, workflow set and default values for requests in the project.
Project members
Define users who are members of the project. Project members can work on a project in capacity allowed by project's permission scheme. 
Permissions
Update permission scheme used by the project or assign a new one.
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