Quick tutorial explaining how to enable the Rich Text Editor (RTE). Also known as the Visual Editor, WYSIWYG Editor, TinyMCE Editor, et al.

Could not be easier, just set the richtext attribute to true, like so:

[usp_content richtext="true"]

Here we have the shortcode for the content field, [usp_content], and have added richtext="true" to enable the WP visual editor. To disable, set the richtext attribute to false, like so:

[usp_content richtext="false"]

That will disable the visual RTE editor, so the content field will be plain-text.

Note: to enable users to include HTML tags and line breaks in submitted post content, you can enable Post Formatting.