I have a house that is going into foreclosure. Was rented but tenants has not paid rent for over 12 months. How is this entered on tax forms

Even though your tenants did not pay you any rent, you can still deduct, on Schedule E, the usual expenses you incurred for the property, however, in this case, the Schedule E will show a loss.

However, you may not show the unpaid rent as an expense - that is just foregone income.