default interactive shell to zsh?

If you got a message, copy the command and paste it into Terminal. Hit return.

If not, here are the instructions: Use zsh as the default shell on your Mac - Apple Support

After you have Zsh configured as your default shell, it does not read the old Bash dotfiles to configure your PATH or other environment variables. The shell Terminal prompt syntax is different from Bash too.

Copy and paste this at your Zsh shell prompt, and then press return to create a Zsh dot file named ~/.zshrc:

<<"EOF" > ~/.zshrc
export PATH="/usr/local/bin:${PATH}"
PS1="%m: %~ %% "
EOF

Then issue this command at the Zsh shell prompt to set the individual PATH and shell prompt as shown above:

source ~/.zshrc

These will now be set every time that you launch the Terminal with the Zsh shell as your default shell. You can edit the ~/.zshrc file in a plain text editor to add additional Zsh shell-related settings.

You can access the latest Zsh manual from here, and the multi-part UNIX man page for zsh is:

man zsh