Web Servers refers as either a Hardware or Software or both of them Working together.

1.On the Hardware side, the Web Server is a Computer that Stores Web Server Software and Website's Component files (for example, HTML documents, images, CSS stylesheets, JavaScript files). The Web Server connects to the Internet and supports physical data interchange with other devices connected to the web.

2.On the Software side, Web Server includes several parts that controls how web users access hosted files. At a minimum, this is an HTTP Server. An HTTP server is a Software that understands URLs(Web Addresses) and HTTP(the protocol your browser uses to view webpages). An HTTP Server can be accessed through the domain names of the websites is stores, and it delivers the content of these hosted websites to the end user's device.

Examples are Nginx, Apache2 and many more.

Apache2 is one of the Widely used Sever, it's a Standard Server. Apache gives the directory /var/www/html/.