In Canada, how much is income tax reduced by charitable donations?
When filing, are there any special requirements to qualify for the deduction or credit?
First, you file using federal schedule 1 and the corresponding provincial form.
Federally, the credit is a dollar for dollar reduction of the tax payable (it is a non-refundable tax credit). For federal tax, the credit is 15% of the first $200 of donation and 29% on all amounts over $200. Be aware that the maximum you can claim is limited to 75% of your net income (the excess can be carried forward 5 years).
See the article at http://blog.taxresource.ca/charitable-donation-tax-credit/