I'm sure you have heard many statements about music publishing throughout your journey as an artist. There is a lot of information out there in regards to what music publishing is. I came across this article by Songtrust on some of the most common misconceptions about music publishing. Definitely give it a read in your free time to brush up on the subject.
Here is the article: https://blog.songtrust.com/seven-things-you-had-totally-wrong-about-music-publishing
It's important to know about the in's and out's of publishing because it's like your "Real Estate" when it comes to music. When you start gaining more traction labels/execs/managers etc are going to try and conquer your publishing. Knowing as much as you can about it will help you make wiser decision in the long haul.