In jira, there is required fields when creating issues, Reason being one of them. I would like to know if it's possible to eliminate it and replace it with another field that does the same thing. Anyone else ever done this before?
It's possible to make almost any field not required, to set up a project so that that field doesn't appear in the issues' screens, and to create a custom field, but I don't see the "Reason" field in our Jira Cloud field list, so it may be a custom field already.
I'll warn you that proliferating custom fields makes administering the system more complex, so think about whether you can fit your process to the existing field. It's not clear from your question what exactly you want your new field to do differently from "Reason".