The reality is that most YouTubers will use stock, library or non-commercial royalty free music for their videos. With this content, licensing is made as easy and hassle-free as possible. One word of caution is to ensure to use well known Royalty Free Music providers and that the license you select covers YouTube use (and if it does on what license basis – check if there are any views limitations for example!).
To get started check out YouTube’s very own audio library. All tracks provided by YouTube are free and safe for content creators to use. YouTube ads tracks daily so this is a great starter resource for you and your video adventures.