Purple/blue tabs are District or School Managed Subject Tabs. Each tab is designated for one or more grade level. Since the tabs are connected to the grade level, they will not show up in an account that does not have any students in the student list in that grade level.
If you do not have the tabs, please check:
Do you have students in your student list?
Are those students (or at least one) in the grade level for which the tab is designated?
If you can, double check with the School or District Admin Account holder to see what grade level the tab is associated with.
If you can, double check with the School or District Admin Account holder to make sure the tab is published.