Possibilities:
Create a picture that has the writing on it and upload it onto the site. Then copy/paste this, with rich text editor turned off, onto the page while substituting the Insert url with the url of the picture you just uploaded. Keep the (') things on though.
<html><style>body{background: url('Insert url') fixed 50% / cover;}</style></html>
Or you could take that same exact thing and use it as a decoration in the background while just typing up regularly on the page.
I have used it for both possibilities. Though you may want to delete the title of the page if you are going to use the first option.
