Using .htaccess you can do many things. This small tidbit will focus on removing and rewriting (mask, hide) the subfolder aspect on a URL to only have the base domain present. You will want to create a .htaccess file if one is not present already in your public_html (or main doc root) for the site.
Yes I like nano! got something with it? Ha. Use whatever you like such as VIM if you prefer. Next you will add the following text to the file.
This will assume you have http://domain.com/sub as where the content you want to load is. And the resulting URL to only show http://domain.com butstill load the content in in the /sub folder. This could be modified many ways to suit the needs for the application at hand.