I have a form for a Client list and want to be able to have a user click a button from that form to open a new item form on a Correspondence list and carry over the unique ID from the Client list. Also to note, the unique ID is not obvious to the user, and it can take 6 fields from the Client list before a record is unique. I didn't see this question on the forum, and am hoping this is straight-forward to put in place. Thank you very much for your time!
does it have to be button? could it be a link?
have a look on this post how to create a link with calc value control