Look over the duvet to make sure it is clean and that there are no tears or rips in it. The duvet should be in good condition, or you may not be able to find a charity that will accept it.
Find charities in your area that accept duvet donations. You can use the Salvation Army and Goodwill websites to find their locations near you. You can also use the Charity Vault website to identify other local charities in your area.
Take your duvet to the donation center of the charity that you have selected. For example, if you are donating your duvet to Goodwill, you can take it to one of their drop-off donation centers. Be sure to request your donation slip if you plan to claim the donation on your taxes.