The Firefox web browser is a free software that allows you to find and visit websites on the internet. It is available for your computer as well as your phone. It was created by the not-for-profit organization Mozilla, whose mission is to keep the internet open and accessible to all. Firefox is an open-source software and supported by software developers across the world.
For your computer: https://mzl.la/34XJEyY
For your Apple phone: https://mzl.la/34XJEyY
For your Android phone: https://bit.ly/2Kso64c
See this guide to learn how to use an internet or web browser.
See this Getting Started with Firefox guide to learn about and set up Firefox.