All devices on the Internet are identified by a unique number called an IP address, such as 184.108.40.206. In case you have a website, the domain that you type to be able to open it is to save you time, however the server where your website files are still has an IP. Due to the fact that there are far more websites and devices than there're IPs, all of the shared hosting servers have a number of sites under an identical IP, while when you use a dedicated server you'll get a dedicated IP as well. Even in the first case though, you will be able to acquire a dedicated IP for your sites and host them on a shared server. One benefit would be that you may get better search engine positions because a dedicated IP generally means a faster loading site. In addition, you need such an IP if you want to obtain an SSL certificate for your website and shield the information that your visitors submit on it.