what kind of cards?
they can be seasonal, home made, store bought, postcards etc.
the type of card is largely irrelevent to the thrill of getting mail.
roxanne's reading level is... maybe 2nd or 3rd grade? she will ask for help reading, so don't worry too much about it.
but she likes the kind of things teen girls would like in terms of like, if you want to draw a picture or cover it in stickers or whatever.
unicorns and puppies and such.
or whatever holiday is coming. she loves whatever the next holiday is.