The Extract action is used for extracting text.
For short text, like a product name or a price, extract as "Only Text". This will simply extract the text between the tags.
If you want to extract a longer text with sections, headings etc. as plain text, but still want the text to appear close to how it appears in a browser, you should extract the text as "Structured Text". If some sort of special markup is desired, e.g. brackets surrounding the headings, then "Structured Text" has rudimentary support for that. If the markup requirements cannot be fulfilled with "Structured Text", then use "Advanced Structured Text" which allows you to set mappings from the HTML tags into your proprietary markup.