Zsh is the default MacOS Shell.
So to add an alias, we need to make changes to the zsh config file that is .zshrc.
Open .zshrc
.zshrc is typically present in the home folder ~/.zshrc
Adding alias
Add the alias to the .zshrc in the following syntax
alias aliasName="command"
Source .zshrc
After saving, source .zshrc using the following command in the Terminal
$ source ~/.zshrc