Add Site Categories

I would like categories added to site. Parts of site will include: 1) Tab Finder Search bar drop down boxes. Search results should work when multiple categories are selected. (Categories on drop down menu should show in alphabetical order) 2) Tab Creator Form should allow users to pick tab category from drop down menu (Categories on drop down menu should show in alphabetical order) 3) Admin should be able to create categories for users to pick from on the creator form. List should show in alphabetical order