They may appear differently depending on your theme and plugins, however these are the two main types on Editors.
Clicking on the Text tab shows the plain Text/HTML code used to show your information on the page.
If you use another site to generate some html code, such as embedding YouTube or Fracebook, you can paste it into the text section, and it will appear on the website when viewing the page or post. Alternatively, you can use this page to design your content, if you are familiar with HTML markup.
Please note: New Lines will frequently be picked up by Wordpress as a new paragraph. Changing between the Visual and Text modes may cause some loss of styling. Use the style sheet provided with the theme to prevent style tags and attributes from being stripped or ignored.
Alternatively, you can use the WordPress Visual/WYSIWYG Editor by clicking on the Visual tab.
Find out more about creating pages or creating posts.
