A CMS (Content Management System) is a type of software used to administer, edit, and publish content on a website without the need of users to be familiar with web programming, markup languages, server settings, or databases. Popular CMSs include WordPress, Joomla, and Drupal.
Typically, users can add / edit / delete pages on their sites, choose or create design templates, administer site settings, and handle most site tasks all through their CMS. Modifying content often uses a WYSIWYG ("what you see is what you get") editor, which allows users to graphically lay out the content on the page similarly to how it will be presented on the website.
CMSs are used on most modern websites since they can enforce standardization, offer collaboration tools, simplify workflows, and reduce the skills and time required by users.
However, if a CMS is not created with SEO best practices in mind, they could have a detrimental effect on the optimization of the site. While offering many benefits, some CMSs can be relatively inflexible when customizations are needed. Therefore, it is crucial to select a CMS that works well with your SEO goals.