Having an understanding of various music licenses is important for independent artists who wish to receive money from their music. Here's a brief summary of common licenses. Be sure to research and  hire legal counsel for your specific needs.

Master License: Right to use pre-recorded song in audio or visual work.
Mechanical License: Right to cover/remix songs, reproduce & distribute music physically.
Print License: Right to print or reproduce sheet music.
Public Performance: Right to broadcast music for the public to hear (radio, restaurants, stores, etc.).
Sync License: Right to use music in video, TV, Film & visual images.
Theatrical License: Right to perform music for an audience on stage.