You can add different types of content to a page or an post. These contents can perfectly coexist, for example text, images and videos. For the latter, please refer to the corresponding help pages.
You can type in text but you can also paste it. By default when you paste text, WordPress will keep some of the formatting corresponding to web standards and delete all others. If you do not want to keep the formatting, first click the Paste as Text button in the editor toolbar and then paste your text either by choosing Paste from the Edit menu in the editor or simply by using the usual keyboard shortcuts.
Formatting the text
You can format the text by selecting it and then using the available tools.