Music for Live Streaming on Social Media Platforms

Hello, i’m new on licensing music for the project.
I’m subscribing to envato elements for a project.
I made a documentary video for my client and they want to publish it as a live streaming on all social media platforms (youtube, facebook etc)
I wonder how i can license the music pre-published and if is it affect the live streaming if i make the license after the live streaming?

Sorry for my english, but hope everyone get it.