How to Create a New Form Category
Go to settings --> forms --> create new category
How to Edit a Form Category
Click "edit category" beside the category name
How to Delete a Form Category
Click "edit category" beside the category name --> delete category.
Note that you cannot delete a form category with forms in it. You can switch the forms to another category by clicking the gray dots to the left of the form and dragging it to a different category, or by clicking edit form properties beside the form and changing the category and clicking update.
Note that forms must be placed in a category in order to be active in your system and visible to users.