To redeem an online gift card from your website, such as Shopify, in-store you will need to do the following:

Setup

You will need to create a payment type for your online vouchers. 

1. On the top menu bar of Retailer, click on Setup → General → Payment Types.
   
2. Click Add to create a new payment type.
   
3. Enter a name for the new payment type. Use a recognisable name, eg. Ecomm Gift Card.
4. Select the TYPE as Charge Card.  Do NOT use voucher.
   
5. Click Next and then Finish.

Processing the Sale

1. Complete the sale to the point of obtaining a Total.
2. Access your ecommerce backend.
3. Access the Gift Card/Voucher system.
4. Access the list of vouchers and search for the Gift Voucher code.   This should enable you to see its status and any remaining value.
5. Click on the voucher and mark it as redeemed/disabled.
6. Back in Retailer, hit Subtotal.
   
7. Enter the entire voucher amount into your newly created Ecomm Voucher payment type in the subtotal screen.

If the voucher value is more than the sale value, the best option is to sell a Retailer gift voucher for the difference. 

For Retailer gift vouchers sold in-store to be used online, we have seen some businesses simply add a message to their checkout that if they are using a gift card generated in-store, to call the business for redemption.