A swept wing is the most common planform for high speed (transonic and supersonic) jet aircraft. The most common wing sweep configuration is a "swept back" profile but forward sweep and variable sweep wings are also in use.
The highly swept wing of a B52. Image source: IANS
In transonic flight, a swept wing allows a higher Critical Mach Number than a straight wing of similar Chord and Camber. This results in the principal advantage of wing sweep which is to delay the onset of wave drag.
A swept wing is optimised for high speed flight. Low speed handling characteristics and lift generation are improved by the addition of High Lift Devices such as Slats and Flaps.