All devices on the Internet are recognized by a specific number called an IP address, for instance 22.214.171.124. In case you have a site, the domain name that you type in order to load it is for your convenience, yet the server where your website files are still has an IP. As there are a lot more sites and devices than there're IP addresses, all the shared hosting servers have a number of websites under the 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 get a dedicated IP for your websites and host them on a shared server. One benefit would be that you will get better search engine positions since a dedicated IP usually means a quicker loading website. In addition, you need such an IP in case you would like to obtain an SSL certificate for your site and shield the data that your visitors submit on it.