We are a 501c3 church. We had a furnace replaced by a heating and cooling company. The bill was $4000.00. They only charged us $2000.00 but wanted the remainder applied towards a donation. My question is, how do I record that?

I am not aware of any particular form, but I think a note from the pastor on the church letterhead acknowledging the donation and the amount should be sufficient. If any parishioners happen to be an accountant then you might want to confirm with them.