The " | include " part only displays lines from the output of the previous command that contain "".
In your case, it would display only those lines of the "show config" that include "elrp". If that single line is all you see, it looks as if elrp isn't configured on that switch.
"show config" has a third option where it shows you the whole 'module' - for instance you could run the command "show config elrp" for elrp settings, or "show config netTools" for sntp settings. "show config ?" would give you a list of all the modules you can see that way.