This is a ‘Vampire’ trick from Max Andrews. A spectator takes one card from a packet of examined visiting card blanks. On one side of the card a panel is printed together with an image of the Devil himself. The spectator signs his name in the panel, seals it in an envelope and puts it in his pocket. Despite these precautions, the name of any selected card will appear in blood red letters on the signed card. Complete with instructions.
Research by Philip Treece has traced the card design back to novelty visiting cards which were advertised by Ellisdons for many years – see the illustration. It would appear that Max Andrews repurposed these cards to create the Satan Writes trick.