Cemeteries are created with the current name of the location.
The category for Milton, Ontario has been in existence since 2018, I did not create it. It does not have the county/region name in the category name. It has a total of 6 cemeteries.
The "Edit text box" is the big box where you add all the text for the biography (not the button you mentioned). To the right of the big box, you'll see a heading "How to Add Sources" then a bit further down, a heading "How to Add Categories", which is where you'll find the link to "request a new category or advice". You might need to scroll down a bit.