BASH (Bourne Again Shell) is the default shell that you will find in Linux systems. ZSH is an extension to BASH that is now the default shell in macOS systems. Zsh is built on top of BASH so it has some extra features. Terminal is the application and BASH/ZSH are the interpreters in the terminal.

To configure the zsh file, we have a file called .zshrc. The rc in zshrc stands for "Run Commands".Using .zshrc you can do things like set aliases, export PATH variables, customize your shell, etc. After a change is made to .zshrc file you have to restart the terminal or type the command source ~/.zshrc in the terminal.

This is a good zsh cheat sheet, go through it!