SEO can be done on various web development content management systems (CMS).
Prefered content management systems that I'd work on is  joomla and wordpress.

Joomla is a cms (Content Management System), a tool for managing content, usually on a Web site, that separates the design, interactivity, and content from one another to make it easier for content authors to provide content)

Joomla  gives the user the ability to create rich content  with the use of various editors available, content with text ,images links PDF tables very much like a word document . These  articles can  categorized to a category which belongs to a section, you can create as many sections &categories as you wish to sort your articles to.
Both categories and sections also Have a rich text editor which   Can be used to write a description and image(s) for each category and section


Sections, Categories, and Articles
One of the most important parts of a website is the content. Now that we have a blank site
setup, let us get some articles on the site! Articles are sorted in two ways: sections and
categories. Sections can contain numerous categories, and categories can contain
numerous articles

Modules
Modules are part of  the main building blocks of a joomla website that are place in predefined positions along each page around the main content. Modules are pieces of code which are written do a set of functions and which is integrated with the joomla framework examples are: a login box, newsletter.


Menu
A website will not do you much good unless there is a menu to help users navigate to
different pages. Joomla! has a built-in system for managing menus. This system is built
around the three types of information in Joomla!—components, modules, and plugins. If
Components are the main information in Joomla! and are driven by menus.
Different menu's can be built for navigation to certain parts of the site, and can be placed in different positions within the Joomla website.


Research shows that 2% of all the website on the Internet are built with joomla and is a favoured cms in Europe, joomla is an open source software. Meaning yo don't pay for the programming of the CMS. Joomla! is Free Software released under the GNU/GPL License.
However many of the modules & extensions are commercial built by 3rd party developers.