Always put PHP code where you want to have the output.
As you do not describe your questionnaire's structure in your question, I cannot be more concrete about pages.
> And instead of the value p should I put the name of the description of the text question I want to add?
The html() function - as you can read in the manual - will simply show the text in brackets. The <p> just makes sure to have that in a sparate line and have some spacing below.
The text() function, instead, will display a text that was previously create in the list of questions.