I love this simple DIY idea for making an envelope.
Use a square paper doily and fold the sides in around your card or invitation. (You can find these at Joanne Fabrics or Michaels Craft Stores) Fold the sides and bottom in around your card or invitation so they overlap slightly. Make sure to leave enough room to slide in your card or invitation. Use a clear glue stick to hold them in place. (See photo for folding example)
Finally, you can add a wax initial stamp, sticker, or label for an added touch to seal your envelope. Simple, inexpensive, elegant, and a truly unique way to set the tone for your special occasion.
Have fun, and then send me a photo of your beautiful creation to post or let me know how it goes!