Install Git on macOS Mojave, Sierra, or an older Mac OSX version by getting the latest git version from the Git home page or from the direct macOS latest link.
This will download the latest version of Git to your desktop/download area as a dmg file, (it says mavericks in the file name but just ignore that)
Open the dmg file, then Control/Right Click the git.pkg file to install.
When Git is installed check in the Terminal, launch the Terminal from /Applications/Utilities and check the version:
git --version
And the version is displayed
git version 2.19.0
To see where it is located
which git
And the location is shown
/usr/local/git/bin/git
Upgrading Git from a previous version to the latest
If you have previously installed Git you can upgrade to the latest version by uninstalling the previous install by using the uninstall.sh script…
/usr/local/git/uninstall.sh
Go through the same process of downloading and mounting the latest git .dmg.
Your previous Git configuration settings and working repositories remain intact.
Trumping Xcodes Older Git
If you have Xcode already installed and have installed command line tools then you already have Git, probably an older version which is distributed with Xcode, this is installed in a path that takes precedence at:
/usr/bin/git
The Mojave version is:
git version 2.17.1 (Apple Git-112)
To run the latest version you need to adjust your shell path so that /usr/bin/git runs after /usr/local/bin
You need to adjust shell path , the path will be set in either .bashrc or .bash_profile in your home directory, more likely .bash_profile
So add into the path similar to the below and keep what you already have in the path, each segment is separated by a colon:
export PATH="/usr/local/bin:/usr/bin/git:/usr/bin:/usr/local/sbin:$PATH"
Restart or reload the Terminal and the newer Git version will now be used.
Learn how to set up a Git workflow with your local OSX client and a remote webserver.
Using Git