When you purchase an online gift certificate, you will be presented with a a form in which you can enter who it is to, who it is from and a personal message to the recipient. Enter the recipient's email in the form, not yours. When the order is placed, an email is sent to the gift certificate recipient along with the Gift Certificate Code that will be used to redeem the certificate online.
When a gift certificate is redeemed, the shopper will enter it in the store's coupon code field. This can be done in either the View Cart Page or during the checkout process. The store will then place the Gift Certificate's amount towards their final purchase. If a balance is left over, their certificate will still be good until the remaining amount is used up on subsequent orders.