This is a recreation of the Holographic Displays plugin.
If you don't have access to plugins like in an adventure map or realm, this is the right datapack for you.
It is easy to use and adds a flare to whatever you use it on.
To get started with the datapack use /function hg:gui_book to get the all important book that will allow you to access the Holograms GUI.
Tutorial Video:
https://www.youtube.com/watch?v=daWR87ZV9wU
Perms++ (Not a dependency but permissions are compatible)
https://www.curseforge.com/minecraft/customization/perms-a-permission-datapack