3819493 - Can we have One Custom Pop-up Message Box in our Expense Reports?

I want to know if we can have a custom pop-up message in our expense reports; for example if a user creates an expense report, before they add any expense, or when they select one expense type, a pop-up message would show.

I want to know if we can have a custom pop-up message box for in our expense reports, either for a specific field, or when a report is created. , KBA , CON-CA-ADM , Administration , Problem