The sample letter given below is a letter which will help you understand what a donation Thank you letter is.

To
[Name of the Receiver]
[Street Address]
[City,State,Zip code]

Dear[Receiver],
We would like to thank you for the generous donation of 1000 dollars made by your organisation. The amount which you donated has provided food and shelter for a number of people who lost their family and houses in the earthquake. We look forward for your continued help and support in our efforts to serve the needs of the needy.
Once again i like to thank you and your organisation as a whole for the generosity and thoughtfulness.

Thank you

Yours Sincerely.

[Signature]
[Your name]
[Your designation]