There are many answers to this question that generally depends on the type of control panel that you are using for your web hosting account. For example, if you are using a cPanel web hosting account, you should always upload your content to the /public_html/ directory for it to be visible on the Internet.
However, if your not using cPanel as your control panel or perhaps have a custom configuration, the upload paths maybe different. Having mentioned this, the public folders are generally clearly labeled in all control panels, and are usually one of the following; httpdocs, www, public_html, etc...
If you have any further questions pertaining to your cPanel/WHM web hosting account, please feel free to get in contact with our web hosting support team for further assistance.