From Atlanta Hartsfield International Airport, you can take the Red or Gold MARTA train lines into the center of town. Alternatively, you can take a taxi for around $30.
If you’ll be taking public transportation, purchase a Breeze card, a reusable card that you can add money to. But public transportation leaves a lot to be desired, so it’s likely you’ll need a car unless you plan on staying within a certain neighborhood. Parts of the city are very walkable, but use caution at crosswalks. Atlanta isn’t the most cab-friendly city, so if you’ll be taking taxis, look up a few cab numbers before you leave or download the Uber app for free on your smartphone.