Find out if there is a local affiliate of the National Furniture Bank Association, a network of donation facilities throughout the United States. If there is not a local affiliate in your area, try contacting the Reuse Development Organization (ReDO), Big Brothers/Big Sisters, Salvation Army, Goodwill or Military Order of the Purple Heart.
You could offer your sofa at an online donation forum such as FreeCycle or FreeShare.
Contact the organization you will be donating to and schedule a pickup or drop-off time.
Determine a fair price for the sofa and get a receipt for your donation.