Termination Penalty Invoice for Relocation Assistance?

[Kevin Huang]

My tenant is breaking lease, because he found a job in another state.
His new employer will pay for the 3-month penalty as part of the relocation assistance, but requires some sort of invoice to show the total amount due.

I'm a private landlord, and don't have any official looking invoice for this purpose.
Does anyone have any suggestions on how to tackle this task?
If you know of any website w/ an Excel template that may do the trick, could you please send me the URL?

TIA,
Kevin

[Kevin Huang]

Thank you Brandon.

I found something nice that others may find useful too:
Rental Billing Statement