All devices on the Internet are identified by a special number called an IP address, such as 18.104.22.168. In case you have a site, the domain that you type to load it is for your convenience, but the server where your site files are still has an IP. Considering that there are far more websites and devices than there are IP addresses, all of the shared web hosting servers have a number of websites under the very same IP, while using a dedicated server you'll be given a dedicated IP too. Even in the first case though, you'll be able to acquire a dedicated IP for your sites and host them on a shared server. One benefit would be that you may have far better search engine rankings because a dedicated IP generally means a quicker loading website. What's more, you need such an IP when you plan to obtain an SSL certificate for your website and protect the data that visitors submit on it.