I'm trying to display the External Identifier of a record on the form to prevent having to double enter it. I'm fairly new to Odoo dev and so I've been searching and found nothing that I could follow exactly, though have attempted multiple things.

The reason is that I have some external data that is produced from a different system that I need be able to import easily. The kicker is that this ID needs to be seen by the user so they can check on the other system if needed to avoid "which John Doe" issues. As the data is obviously already tied together, I know there is a way to do it but I'm at a loss of how. 

Thanks for your help!