# add following line to ~/.zshrc file & restart your Terminal application:
autoload -Uz compinit && compinit

# Alternatively, you can run following two commands in your Terminal 
# application to add necessary line to .zshrc file and restart your shell.

echo 'autoload -Uz compinit && compinit' >> ~/.zshrc
source ~/.zshrc

# Git tab autocomplete is now enabled on your Mac.