How Do I Write A Letter Requesting A Donation For My New Company?

You could use something like this...but again, I have no idea what type of company or what the donations are for:
Dear Mr. Smith:
"My Company Name" is a "Type of agency" agency in this county serving the needs of "i.e., families at risk". We recently purchased a building but it needs major repairs and renovations to comply with city building codes. The counseling office also needs office furniture and equipment, especially a photocopier.
Your company can help us by providing funds in the form of a grant or by donating goods and services. A copy of our tax-exempt certificate is attached.
Thank you in advance for your support.
Sincerely,
xxxxxx~

Hope this helps or gives you a starting point.