Copyright laws are very strict in the world. Especially when a creator uses music and video of other copyrighted owners. Using copyrighted content without caring may result financially claim by the respective owners. YouTube may cancel your monetization account too. Your YouTube channel gets a strike for it. So knowledge to fair use of music in YouTube videos is perfect choice.
As a Youtuber, you should have information to use music fairly. Even various videos are made by YouTube to guide the YouTubers regarding it. Watch given videos before using copyrighted content (video or music). Otherwise it may harmful for you (claim by the respective owners). As a result of it, your hardly earned monetization account may be closed by YouTube.
Watch these videos :
Triople 