Step 1: HTTP stands for HyperText Transfer Protocol. It is the application-layer protocol that a web browser and a web server use to exchange web pages.
Step 2: Its main function is to request and deliver web content (HTML pages, images, and other resources), which is what makes browsing web pages possible.
Step 3: Eliminate the rest. Sending emails uses SMTP. Converting domain names to IP addresses is the job of DNS. Transferring files securely is done by protocols like SFTP or HTTPS/FTPS.
Step 4: The main function of HTTP is browsing web pages.