Every time you visit your favourite website, you’re in contact with a web server -a program that figures out what content you’re asking to see, and then sends it to your browser. Any computer can act as a web server, but the trend is to have a company that runs servers that host your site for you.
Web servers need to be on all the time so visitors can access the site -hosting companies specialize in keeping servers running and connected to the internet 24 hours a day. It’s also much cheaper for a hosting company to run one server that could potentially host hundreds of sites than it would be for each of those sites to be hosted privately.
Finally, the hosting company takes a lot of the worry out of hosting a site by making sure their servers are secured to the highest standards.
Most of the world’s websites use a “virtual hosting’ system. In this case, a server at a particular internet address holds many websites. All the domain names (the names in words that end with .com, for example) for those sites point to that one server.
Whenever you visit a page, your browser makes a point of telling the server which domain name it used to find it, allowing it to figure out which of the thousands of pages on its disk to send back to you.