This is an easel card. It stands on its own and also folds down nicely into an envelope. You can learn how to make one here. I just adjusted the dimensions to make a 5×7 card because I already had 5×7 envelopes.
Details: Hello Kitty cut at 4.5 inches and “Happy Halloween” and shadow at 1.75 inches. Cardstock: Joann’s Value paper.