If you have received a Gift Card from a friend or loved one, it is not necessary to register as a Shopbuddies user to make use of it.
The person purchasing the gift card for you, will share it with you by sending a link. They can share this via messaging channels or through email. You as a receiver can click on the link and specify which email address you want the gift card sent to. After confirming, Shopbuddies will send the Gift Card to your specified address.
You can however, choose to add the giftcard to your Shopbuddies account if you have one and keep all your Gift Cards easily at hand in the app.
From here, you can enter this on the merchant website to redeem the gift card and spend it!