Note how the line ends with a backslash. That is escaping the newline so the command isn’t executing immediately. The next line begins with a pipe which is taking the input. It’s a way of separating multiple piped commands over several lines for readability. In other words, these are equivalent:

  echo 'Something or other' | sed 's/or/and/'

and

  echo 'Something or other' \
    | sed 's/or/and/'