The Safari web browser comes pre-installed with Mac OS X, but other alternatives exist. Choosing your default web browser is a matter of personal preference and this tutorial explains how to edit this setting in Mac OS X.
The first step is to download the web browser software you want to use and install it on your Mac:
Firefox for Mac OS X
Google Chrome for Mac OS X
Opera for Mac OS X
As from Mac OS X Yosemite, this setting can be changed via Safari's settings:
and then click on the Safari
menu > Preferences
tab. Click on the Default browser
menu and make your selection from the software installed on your Mac.