If you are able to browse the world wide web, then you maybe using a web browser. Web browser is basically a client or software that communicates with the interconnected servers across the world and is able to render the 'code' over the network and interprets the 'code' into pleasant view for the users that browses a website or domain.
Upon buying your computer, the default operating system has a specific web browser. Windows has Internet Explorer, Mac has Safari, and Linux has Firefox (Although it varies on the version of Linux) installed by default on the system.
Even though there are default web browser depending on your operating system, these web browsers can be disabled or change by downloading other web browser that is available on the internet.
