1.    Download Github For Windows client and install it.

2.    After The client successfully installed, connect it to your GitHub account.It should be easy, just follow the wizard.

3.    Then you should add git.exe location to your "Path Variable". The location you should add will probably be something like :C:\Users\Your_Username\AppData\Local\GitHub\PortableGit_ca477551eeb4aea0e4ae9fcd3358bd96720bb5c8\bin

Alternatively, if you don't want to add to environment variables. You can open the android studio and go to : Settings -> Version Control -> Git In text box next to "Path to Git Executable" you will see "git.exe" , just give it a full path like so :C:\Users\Your_Username\AppData\Local\GitHub\PortableGit_ca477551eeb4aea0e4ae9fcd3358bd96720bb5c8\bin\git.exe

Hope it saved your time. Happy coding :)

EDIT: For latest Github for Windows versions some can find the git.exe under "...\cmd\git.exe" rather than "...\bin\git.exe".