When constructing the actual message to be sent you might to start a new line, or you might want to use quotation marks. Here's how to do that:
To create a new line use
\n
To escape quotation marks or other character use
\ (a single backslash)
If the given methods don't work there might be an editor issue. Perhaps your editor is adding hidden characters. Try using standard editors like Gedit and Notepad.