Performing editions are scores that have been edited by publishers and teachers / performers to include fingerings, phrasing, and sometimes tempo indications. Performing editions range in quality, but you'll find that publishers such as Henle, Wiener Urtext*, Breitkopf and Hartel (among others) tend to put out better editions.
Some words associated with performing editions include:
*Urtext is a German term meaning first/prime/original (text); these editions have very little editorial intervention with the intention that in this way they represent composer’s original intentions.