Is there more than one config.yaml file?

When I installed Home Assistant, the config file held little in it. I am now trying to set up Duckdns and part of the instructions say…" Next, using the File editor, open the configuration.yaml file, uncomment http by removing the hashtag # and then enter the following below it:"
Trouble is, I dont have a “http” entry so I wondered if perhaps there was a “hidden” config file I should be looking in for it?

No there is only one.
But maybe your configuration does not have that line. Just add it.
Configuration.yaml is a file that is different between each setup. Nobody has the same config.

OK, thank you.