If you host a website on a server, it uses the server's shared IP address - a special number which is used to detect any kind of device connected to the Internet. The website name that you use for the site is for easy access and convenience of the website visitors, but on a more basic level, their browser connects to the IP address of the server. Due to the fact that there're a lot more websites than IP addresses, shared web hosting servers use a single IP for multiple sites even in case they are owned by several users. While this doesn't affect the website performance directly, using a dedicated IP may slightly boost the loading speed of a certain website, providing it better rankings in search engine results. Such an IP is necessary for the setup of an SSL certificate too, so if you wish to protect the payment or login info that your site visitors submit, you'll need an IP together with the SSL.