Here is a sample template you can use to write an acknowledgment letter for receiving a donation.
To [Representative of the donor]
Dear, [Representative of the donor]
We would like to thank you for your generous contribution of [Item/Amount donated] on behalf of [Reciver name] which was received on [Date].
Your generous donation has made a significant impact on the acceleration of our goal to [Specific goal]. Your support is invaluable to us and we would like to express our gratitude for your contribution.
You can find more information about our organization on our website [Insert website]. Your contribution to our cause will have a positive impact on many people.
Thanking you again.
[Name of receiver organization]