A Content Management System (CMS) is a commonly used piece of software for editing the content within a website. They allow non-technical users to create and edit websites.
Popular CMS’ include:
WordPress
Drupal
Joomla
Shopify
Squarespace
Wix
Magneto
Sitecore
Adobe Experience Manager
Craft CMS
Umbraco
Duda
There are likely tens of thousands more, as many organizations have developed their own proprietary CMS. Several of the most popular CMS’ are freely available.