To make a Private Rap public, go to your profile and click on “Private Raps.”
Go to the rap that you want to make public. Click on the three-dot button in the top right hand corner on the rap cell. This will bring up several options such as Share Rap, Send As DM, Rename Rap, etc. Tap on “Make Rap Public” and it will switch your rap from your Private Raps to your Shared Raps on your profile.
If you want to make your Shared Rap private, follow the tips above but choose “Make Rap Private.”