Many Project Managers track where a Project is in its project life cycle based on completed tasks.
For example, "if Task A and Task 24 are complete, then we're in the Next Phase."
You can then run reports with this automated information:
Add this add-on in the Administration > Add-Ons > Get more Add-Ons:
Click Install, then Configure:
Enter the names of the phases to select from:
From there, any Project Manager or PMO manager can select the Phase from the Task Add/Edit page only on the Advanced tab:
Do this on the template to reuse these phase settings over and over or change it project by project.