I am wondering if there is a way someone other than the creator can access and edit the game? Please tell me if there is a way to do this. Thank you 
Ofcorse, you just need to copy entire project directory to other person computer, with exception of few directories:
-Intermidiate, which contains in process and cache files, usually dedicated for your computer use only, it may path stuff outside of project directory
-Saved, contains local configuration and well as logs, they be generated based on local UE4 configuration so it’s not needed and may mess things up for people too
-Bineries, this is optional, if you have C++ project, generally project user should generate dll file for there engine version, thigns is artist might not be willing to install VS to build it, if you build dll using laucher version you can keep this directory for them to use that dll
-VS files in main directory, if you have C++ project you will have VS files in main project directory, smae as Intermidiate those are dedicated only to be used with you installation of VS, other users wount be able to use them until they generate there own VS files. Generally you should only have uproject file in main directory
Here some random examples of project sharing in github:
For collaboration you should use source control systems, either Git, SVN or Perforce (that last one is most recommended as UE4 assets are binery and git repository without LFS grows very fast)
EULA only prohibits redistribution of the engine it self, each project user should have there own installation, but projects are free to share as long as they don’t contain any UE4 engine files, anythings that laucher installs when you download engine and everything that is in github UE4 repository. This also includes other licensed and copyrighted stuff you put in your project, you need to follow the rules of there respective licences