A marksman in League of Legends is a champion with high physical damage-per-second that deals most if its damage with basic attacks. Marksman are the primary damage source on any team for killing champions and structures alike. The downside of being such a carry is that everyone on the enemy team wants to kill you, making positioning well a key quality in any good marksmen.
One of the current strongest marksmen and one of the original champions in League of Legends is Ashe, the Frost Archer. Ashe is a marksman that gets most of her damage from her auto-attacks and her volley of arrows. Ashe is considered a utility carry because while her damage is pretty good, she excels with crowd-control in her slowing auto-attacks and her ultimate, Enchanted Crystal Arrow, which is an Area of Effect Stun. She also has the ability to scout vision with her Hawkshot. Ashe can kite enemies with ease and help initiate team-fights from far away, making her a very safe pick.
Another type of marksman is the hyper-carry. Jinx, the Loose Cannon, is an example of a hyper-carry, which is a marksman that scales well into the late-game due to some form of innate steroid and high late-game damage. Jinx can struggle early due to her immobility, but can farm from a safe distance using her rocket launcher. In team-fights, Jinx’s goal is to deal massive damage from a safe distance, and becoming super mobile with her passive, which grants movement speed on champion kill or assist. What she lacks in early-game damage, she makes up for by being a late-game monster.
If dealing massive damage from a distance and being focused by the enemy sounds like your kind of play-style, try playing a marksman!
To learn more about another role, check out this guide on tanks!