Do you remember what I told you about the internet? If you are new then I would recommend the below article to read first.

https://blogs.deepeshdg.com/what-exactly-is-the-internet-and-how-does-it-work

The internet is a worldwide network where we can retrieve and send any kind of data over the network from one computer/device to another computer/device.

Over time, those computers which send data became important and they needed to be specially configured so that they can serve data fast and efficiently. Then a special operating system was created which is known as the server operating system (Server OS). There are many server operating systems available out there such as Windows Server, Ubuntu Server, RedHat Server and many more.

Only the operating system makes a computer a server or a normal computer (client). You also can convert your normal computer into a server by installing any Server OS and configuring the necessary steps. If a computer has a server operating system installed, it is known as a server. The server is just an operating system or computer program that serves the resources and data to its user also known as the client. Whenever a client requests any resource from the server, the server uploads that resource and the client download that resource.

One more thing, a computer can not run files online, you can never run files online, if you watch youtube videos, your computer first requests that video from the youtube server, that server first authenticates and then returns the video as a response, youtube server uploads video and your computer downloads that video in the form of cache and saves it into your secondary storage device (Hard Disk or SSD) and then your browser able to run that video. The same process goes for any kind of online surfing.

Suppose you have some movies in your pen drive and you want to watch them on your computer. What will you do? You will simply insert your pen drive into your computer, copy-paste movies and start watching them. You transferred some data/files from your pen drive into your computer that is physically connected.

Now suppose you have two laptops and you need to transfer movies from one to another and you don't have a pen drive. How will you transfer? You would need to somehow physically connect both laptops with wire (LAN) and transfer movies. What if one laptop is in another city, another country or another continent, how will you connect both laptops? Would you use thousands of miles of long LAN cable to connect?

This problem was very huge and we needed to somehow connect every computer in this world to each other so that data transfer could become easy. Then some big investors gathered and made a company that laid thousands of miles of long cables across the ocean and connected every continent, and every country to each other via those cables. These companies are called Tier-1 ISPs (Internet Service Providers).

All countries are connected. Now, it's time to connect states or provinces within a country. Companies that connect interstates via internet cables are called Tier-2 ISPs (Internet Service Providers). and companies that connect intercities via internet cables are called Tier-3 ISPs (Internet Service Providers).

Tier-3 companies provide internet services to the end-user in the form of broadband/wifi so that you can access every computer in every city of your state because Tier-3 ISP only connects cities in one state. Tier-3 ISPs make deal with Tier-2 ISPs and rent national internet cables so that you can have access to your whole country's internet. And at last, Tier-2 companies rent international internet cables from Tier-1 ISPs so that you can connect to the whole world. Tier-1 ISPs charge from Tier-2 ISPs, Tier-2 ISPs charge from Tier-3 ISPs and Tier-3 ISP's charge from the end-user to use their internet services. Those internet cables also connect to all SIM towers so that you can access the internet from your carrier sim card.

Now you know that the whole world is connected through wire cables. That's where the term "web" (a spider web that connects every point) came from. A web that is connected worldwide ( www - world wide web).