Learn how to make a piping bag out of parchment paper. Parchment paper pastry bags are perfect for cake decorating, especially piping small details, fine lines, writing without a tip, stringwork and f (How To Make Butter Cream)
pick a font you like, print it out, cover with parchment and then use melted chocolate to pipe out the words on the parchment. Put it in the freezer for a bit. After it can be carefully picked up and placed on the cake with a bit of chocolate.