IRS Letter of Determination

The Young Women would like to do a service project in our ward. The business that they contacted requires the tax exempt ID and an IRS Letter of Determination. Is anyone familiar with this "IRS Letter of Determination"? How should I go about getting it? Has anyone had to get one of these before?

Thank you

It appears that the IRS letter of determination, is just the letter from the IRS stating their decision after an application for tax exempt status has been submitted. (see this link.) As for getting them, I am uncertain how to go about doing that.

A member of our stake needed the IRS tax exempt number in 2006. He called HDQ and received a letter from the Director, Tax Administration.
The number was 801 240-5208