To Manage your categories and sub-categories, You need to go to Settings > Proposal Settings > Wedding Categories.
Edit a category/sub-category
First, click on edit to the right of the category or sub-category.
Next, make the desired edits on each category. From here you can delete a category/sub-category or change the text for each. After making the desired edits, click submit at the bottom of the form to save the changes.
Add a Main Category or a Sub Category
Click on "Add new" located at the top right of you screen. Select the type you want to add if it's a category or a sub-category ( if it's a sub-category that you're adding, you'll have an additional option to where you want it to be under which Main Category ).