This is one type of machine embroidery that is quick and cheap to do so experiment as much as you can! If it doesn't work it can go in the recycle bin! I've stitched on card, handmade paper and paper doilies and all have been successful with a bit of trial and error. You need a really simple design for card (look for a low stitchcount) but something a bit more complex works on handmade paper. If you are making a greetings card, you can stick the embroidered paper to the card. This saves putting a card backing on to cover the back of the embroidery. There are some good designs in DBC to get you going. Look out for a lovely rose digitised by mops. If you try a design and some parts of the design are a bit too dense, try enlarging the design by 10%. This will make the stitches a bit bigger and reduce the problem. Enjoy experimenting!
See you've been given the tutorial....special stablizer and designs. Heavy designs will tear through the paper, guess I should say cut out your design and leave a hole where it was...you need to look for designs for cards
Well, I didn't see where it told about hooping so here is just my thoughts cause I know the right answer is out there. You could hoop tear away then spray adhesive (the kind for fabric that we use in embroidering) or use small pieces of painter tape (less likely to stick too well) to hold the card stock to the tear away. Good luck!
Oh yes, as ktthwk4 stated you must use designs that were made to be sewn on cards otherwise you will just have a mess of thread and a big hole when you finish.
a tutorial