When creating a new ad, the custom fields appear below the User Information fields in the form. It should appear in the listing details below Description.

Custom fields are shown in publish page via hook that is common for all extra data.
Typicslly shown at bottom of publish page.

Is there a way to move additional custom fields up? And maybe put a title above it like "ADDITIONAL INFO" or "MORE" above it in H1/H2?

Would this plugin work?

https://osclasspoint.com/osclass-plugins/backoffice/hooks-manager-plugin-i78

@jasongeek
No, as plugin allows to shift functions inside hook, not hook itself.
Only what would work is to edit item-post.php in theme and move hook position there, but as I told, all functions here use same hook. Could work well just in case you have only custom fields there.

Is there a template file I can edit to put it above ad poster's information? What template is it in?