As a main manager, you can delete custom columns from the project.
However, this will also permanently delete all data contained in the column. For this reason, it might be worth deactivating the column instead, which will make it unavailable to view and edit, without losing data. See Activating project columns for more information.
1. Click More in the project view and choose Customise project.
The Customise project dialog box opens.
2. Select the Column management tab.
3. Select any custom column in either the Available columns or Activated columns list.
4. Click Delete.
A warning message appears, asking you to confirm the deletion.
5. Click Yes.