All devices on the World Wide Web are identified by a specific number called an IP address, such as 18.104.22.168. In case you have a site, the domain name that you type to access it is for your convenience, yet the server where your website files are still has an IP address. As there are many more websites and devices than there're IP addresses, all of the shared web hosting servers have a number of sites under an identical IP, whereas using a dedicated server you will have 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. An advantage would be that you'll enjoy superior search engine positions as a dedicated IP often means a quicker loading website. In addition, you need such an IP when you intend to obtain an SSL certificate for your site and secure the information that visitors submit on it.