To answer this question with a sentence or two would be a disservice to your question.There are different types of producers. As a producer myself, I came up through a time where you needed a multitude of musical skills. Being able to write and arrange for various instruments, help in song selection, help in arranging song, deciding tempos etc. That's a hands on producer. And my job was the responsibility of the music and the artist. I always work with engineers I trust so that I can focus on the music and not the technical aspects.
Nowadays you have producers who can manipulate samples and loops and call themselves producers since they have a computer and some software. Don't get me wrong, there's an art to that as well. If this is your avenue then you should be prepared to not only focus on the music but to record, mix and sadly master. I say sadly because I hear so many things that were mastered at home in studios that are not tuned or have any treatment and sound horrible.
Hope this helps.
cheers,
Buzz