Hello. Can i create a game with my friend in this same time?
Please Help. FASTTT.
Yes you can.
Thank you for your answer. But I mean more that like me, for example, I write scripts and a friend makes a map. And when I finish scripting, he can see my scripts and I see the map he built. Thank you in advance
The original answer was correct and is the way most people do this.
You can also do live map editing Getting Started with Multi-User Editing | Unreal Engine Documentation and it talks about source control as well.
But i have 4.12 unreal engine. And in plugins doesn’t have this plugin.
(Im From Poland No Hate)
No hate 
You can still use source control.
I Doesn’t have plugin 
Why are you running a 3 year old engine version?
But in 4.15 or newest version doesn’t have normal one script. And i install 4.12 to do one script.
You can still use source control outside of the editor. The plugin just makes it a bit easier.
HOW!!!
Too big of a topic for here.
Git for UE4 / Unreal Engine 4 - YouTube This video shows how to do it. It also covers the plugin… but how to do it with a GIT client outside of UE4. There’s a lot of documentation \ tutorials out there on how to use source control.