Good question, did someone else set the site up for you?
It looks like WordPress is installed in a /wordpress/ folder on your server.
You’ll want to:
1. Go to “Settings > Reading” and change the URLs to yoursite.com instead of yoursite.com/wordpress – NOTE: This will make your site unreachable until you complete step 2.
2. Move all files from the /wordpress/ folder to the root folder (up one level).
First, I would delete any index.html-like files you have in the root, which is probably where the iframe is coming from.