Add custom fields in the new and edit the site forms without touching the WP core

Question

I am working on a custom plugin to add some extra fields in each forms of user and site. Therefore, I need to add few custom fields in the both new/edit site and user forms. Just to know if there is a way to add custom fields when I create or edit the site and users through Network admin panel without touching the WP core.

Answer 1

Of course you should never touch WP core. If your custom fields within your custom plugin - just add it :) If you are talking about custom fields in native WP forms you should read about WP hooks mechanism.