Help:Introduction to editing with Wiki Markup/1
Editing pages
Activate editing mode
Formatting
Keeping it tidy
Wikilinks
Connect pages to each other
Saving your changes
Publishing
Creating new articles
Building a page from scratch
Summary
Review of what you've learned

Wikipedia is formatted using its own language. It's pretty simple to learn if you want to. Otherwise, you can use VisualEditor, a simpler editor interface that works like a word-processor]]
To view and edit a page's source code, just click "Edit source" at the top of any page. This will allow you to type in the text that you want to add, using wiki markup to format the text and add other elements like images and tables that are explained later in this tutorial.