There are two files that needs to be touched to make this smooth.

1. ~/.gitconfig

2. .bashrc or .zshrc (This is optional. You can use only if you need more customized alias)

Let’s start with ~/.gitconfig

Enter the following in the command line. This will set the values in .gitconfig automatically

git config --global alias.co checkout  
git config --global alias.ci commit    
git config --global alias.st status    
git config --global alias.br branch

For the second one open either of the file ~/.bashrc or ~/.zshrc and paste the one below:
alias gck="git checkout"
alias gco="git commit"
alias gst="git status"
alias gb="git branch"

Restart the terminal and test it out.