How to have log in screen like this and where to put it?
I don’t quite understand what your asking, could you elaborate a bit more?
I mean how to have that screen before the multicharacter selection after the loading screen.
It’s like a welcome screen.
Plenty available on the internet. Just look up loading screen fivem. Instructions on how to add them should be in their files. All are server-sided scripts means that you need to have your own server, you can’t just add to see it every time you log in.