Once per turn when you roll damage for a ranged weapon, you can re-roll the weapon’s damage dice and use either total.

In addition, when you are wielding a ranged weapon, you can make a special attack with that weapon as an action, a vital strike:

Vital strike. On a hit, you gain a 1d8 damage bonus if you have the extra attack class feature. This damage bonus increases to 2d8 at 11th level and 3d8 at 17th level.