Almost all fish commands respond to the `-h` or `--help` options to display their relevant help, also accessible using the `help` and `man` commands, like so:
\fish
echo -h
echo --help
# Prints help to the terminal window
man echo
# Displays the man page in the system pager
# (normally 'less', 'more' or 'most').
help echo
# Open a web browser to show the relevant documentation