There are a few minimum requirements – your channel must have more than 4,000 public watch hours in the previous 12 months and more than 1k subscribers. For more info check out the YPP application checklist here: https://yt.be/help/ECX1 . Hope this helps clarify!
Copyright owners may choose how they want to enforce their rights on a video-by-video basis. You can remove the claimed content from your video w/ editing tools. Here are detailed instructions: https://yt.be/help/xXML