Choose the charity to which you would like to donate your furniture. Although Purple Heart, a national veterans service organization, and the Salvation Army, an Evangelical organization whose stores profit their adult rehabilitation centers, are the two most prevalent charitable donation sites, there are plenty of charitable donation centers willing to take your donations, including Goodwill Industries and St. Vincent de Paul.
Verify that the charity or company you'd like to donate your furniture to is legitimate. Checking with the Better Business Bureau's Wise Giving Alliance is one way to ensure that it is.
If you are physically capable and have the vehicular means to do so, safely load the furniture into a truck and drive it to a local drop-off spot during open donation hours, which you can usually find online or by calling the organization. Many thrift shops recommend calling ahead to ensure that your nearest location has the space for your donation.
If you are not capable of bringing the furniture to the drop-off location, scheduling a pick-up time is your best bet. Both Purple Heart and Salvation Army will pick up your furniture from your house during a scheduled appointment time. Check with other organizations to see if they offer pick-up service.
Once your furniture is donated--whether via drop-off or pick-up--make sure to request a tax receipt for the charitable donation.