Placing the card on the outside is fine, however, make sure it is secure. Tape it down on all four corners. Better yet, have the gift delivered to the bride way before the wedding. Years ago it was a tradition to have the couple open gifts at a wedding. Today there is limited time. Possibly the couple will live in another town, so transporting the gifts can be a hassle. Sending gifts to the address the couple will call home is the best. Gift cards and checks are always appreciated and easiest for guests. If you insist on a specific gift, encourage that the gift card be used for it.
