FAQ (we ask the web)
Table of Contents
Change Shell
$ sudo chsh -s $(which zsh) $USER
chsh is the command to change shell. 
-s is the flag to specify the shell. 
$(which zsh) is the path to the shell you want to use. 
$USER is the user you want to change the shell for.
Add a directory to PATH
$ export PATH=$PATH:/path/to/directory
In .zshrc / .bashrc or similar (*_profile)
export PATH=$PATH:/path/to/directory
Example: $HOME/.local/bin like what zoxide suggests.
export PATH=$PATH:$HOME/.local/bin