To access Workflow and manage default statuses, you must have the ‘Manage system settings’ permission enabled in your role. How to enable permissions, see Roles and Permissions.

Adding statuses is part of workflow.

To add a workflow status:

1. Go to User Menu | Company Settings | Workflow.
2. Click '+ Workflow' green Button at top of the page.
3. Type a name for the new workflow/status.
4. Select a type for the status: Treat as Open, Treat as Completed, or Treat as Hold.
5. Select what items the status should apply to: Portfolio, Project, task, Issue, Request, or a combination of these.