All crossbows have a 50% chance to stagger enemies, which increases to 75% if you unlock the Power Shot Perk. The crossbow can also be enchanted with any effect for the ranged weapon category in addition to this.
You can get the Crossbow and ammunition (Bolts) for it, in Skyrim at one of several locations:
During the "Dawnguard" quest, the Orc Durak will give you a crossbow and 45 steel bolts if you talk to him. If you don't talk to Durak, Isran rewards you with a regular crossbow and bolts at the quest's end. If you talk to both, you can get two crossbows and 90 bolts by removing Durak's crossbow before talking to Isran.
Members of the Dawnguard Faction use crossbows which can be taken from them once defeated.
You can find a couple of Crossbows in Fort Dawnguard, one is in the lobby on a wooden crate and the other is upstairs on the castle battlements.
How to Start the Dawnguard
Crossbow Gameplay Tips And Tricks
The crossbow is a strong weapon but takes longer to reload compared to most bows.
All crossbows have a 50% chance to stagger enemies, which increases to 75% if you unlock the power shot.
Crossbows also make more noise than bows when fired, so they aren't great for sneaky attacks.
Some weapons in Skyrim are Levelled. The power of a levelled weapon is based on your charcters level when you get them. Some get stronger in both physical and magical aspects, while others only improve their enchantments. These items don't get better as your character levels up.