After submission, you can go back and edit the Title, Description and Supplemental Information… but no way to go back and edit or correct the Category / Categories… if you can update those 3 fields, you should be able to go back and correct/edit them once submitted… Its a lot easier to, say, sit down and correct these after submission at your desktop… if you punch in the wrong thing on mobile while you are trying to type, take photos, etc… it can easily be overlooked… so being able to edit / correct it would should be added to the edit function. Please make this happen.
Welcome to the forums.
The category has no value to any player of any Niantic game and has never had any value or meaning. Ignore it beyond having to choose something when submitting in Pokemon Go.
It would be wonderful if Niantic could remove this question, as people (quite reasonably) think it has meaning and some people think it lists eligible things (it doesn’t). Plenty of people make mistakes because of the list of categories and it provides zero help to the wayfarer.
Using the web submit method, you don’t get asked for a category.
Also, if you use the web submission flow, no category is required.