I have a custom object called "Branche" which contains a number and a description field. My Account page layout contains a lookup field to this custom object. Currently, it shows just the number. How can I make it show the description and the number at once (or any other field for that matter).
You can add the field to "Branche" Lookup Dialogs in Search Layout and then you will see the field while searching for Branche records
When you add fields to lookup dailogs.
Then you will see something like this.
