Becoming a werewolf in Skyrim is an easy task, since you can either get attacked or do a set of quests to turn into a werewolf.
If you’d rather do the quest line, it starts inside the Jorrvasker in Whiterun. Talk to Vilkas to start the Companion’s Quests.
During the fourth quest in the storyline, The Silver Hand, you have the opportunity to become a werewolf.
The perks of becoming a werewolf are many. You become a superhuman who doesn’t need armor or weapons, since they are already built into your body. Your super smelling allows you to smell the blood of enemies in the area.
Just as you contract lycanthropy through the Companion’s Quests, you can also get cured through this quest line. The final quest, Purity, sends you on a mission to kill a witch. Beware that once you cure yourself, you can never go back to being a werewolf.
References:
How to Become a Werewolf in Skyrim