How do you make a card clickable?
You can wrap block elements with <a> . It is valid HTML5 and renders your card clickable. You may need to adjust the css rules for the text inside this block however.
Should entire card be clickable?
A whole card CTA is useful as it is a large tap area, but other than that it introduces a lot of accessibility issues and I would encourage you to avoid it in most circumstances. If you make your whole card clickable (i.e. a hyperlink) then all of its content becomes the link text.