Navigation:
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Go to Setup >> Plan Items.
A> When you Click on Category and you Will have the below option.
1> Click on Add new in order to add a new Category.
2> Click on the Drop down to select a Plan type .
3> You will have the option to edit a Category and Deactivate a Category if you do not use them.
B> : When you Click on Sub-Category and you Will have the below option:
1> Click on Add new in order to add a new Sub - Category.
2> Click on the Drop down to select a Category.
3> You will have the option to edit a Sub-Category and Deactivate a Sub-Category if you do not use them.