How do these youtubers do it?

[Big Daddy 43]

So how do I mod like these rappers do? I've installed a car pack or two, but then quickly banned from online game play. So How do I go about doing this?

Private servers?

I own a original and legit copy of GTA V if that helps.

[drlq99]

you cant play online with mods.... they play on fivem, which is a modded gta 5 multiplayer game