Song Licensing.
When sharing video content online you need to use "copyright free" music to maintain that your videos are abiding by the copyright laws
Instagram, youtube and facebook have started to really crack down on this over the past few years and will remove videos that contain unlicensed tracks.
Trying to obtain a license for a popular artist's song can take months and months, and cost you anywhere from $1,000 - $100,000+ depending on the song!
So if you use copyright tracks in your ads... they may not get approved.
If you share a video on your social media with a copyright track, it may get posted... but could be taken down within a few days or even a few months!
If you get multiple copyright infringements on your account (whether that's youtube, instagram or facebook), you may have your account suspended/permanently deleted.
Generally speaking, I will share a few song selections based off of the genre/vibe that has been pre-spoken about prior to shoot date so we are both on the same page. You can choose to be involved in the process or not as involved but ultimately it needs to be a song that can be licensed through one of these sites.