7 Best Free and Open Source Web Servers
At the most basic level, whenever a browser needs a file that is hosted on a web server, the browser requests the file via HTTP. When the request reaches the correct (hardware) web server, the (software) HTTP server accepts the request, finds the requested document, and sends it back to the browser, also through HTTP.
Nowadays, sites use HTTPS (Hypertext Transfer Protocol Secure). This is a mechanism that allows your browser or web application to securely connect with a website. HTTPS is one of the measures to help keep your browsing safe and secure.