Content Management System or simple CMS are known as website designing frameworks/software or systems. These frameworks are designed for those people who aren’t familiar with website design or complicated code that will usually design a great website and allow them to operate a website easily without having to worry.
CMS Open source programs are most popular because they are completely free and have many templates, themes, extensions that make them more functional
Some most popular CMS website software are Joomla, WoorPress and Drupal. These CMS are incredibly easy to use and offer thousands of themes from different designers that can be easily modified as per your requirements.