WordPress makes use of a standard editor known as TinyMCE. The MXE part stands for Moxiecode Content Editor. It is a platform-independent, web-based, editor with both visual WYSIWYG (what you see is what you get) and text (HTML) sections. This open-source editor is designed to integrate easily with content management systems (CMS) like WordPress.
Although limited in its function selection, it has a familiar interface and is quickly learned. If you are looking for greater features is is suggested you install the free TinyMCE Advanced plugin.
These eleven videos cover the features and functionality of the standard TinyMCE editor.