Keep in mind that the MCF Shipping app has a few requirements. One of those requirements is that the product SKU’s in Shopify match the product SKUs in Amazon Seller Central. When a store creates an virtual bundle as a FBA product in Amazon Seller Central platform allows that merchant to sell and ship that virtual bundle on Amazon.com. But, remember when you sell your FBA products on a different website other than Amazon, you are now using the Multi-Channel Fulfillment or MCF program. So the rules are different.
Which means when you create this Amazon virtual bundle product in Amazon Seller Central, that product still does not physically exist. And in order for the MCF Shipping app to send the correct fulfillment request for your Shopify orders to Amazon, we need the correct SKUS, and we need those SKUS to be in stock and actually exist in an Amazon warehouse!
Inside of the MCF Shipping app. Navigate to the Home Page of the app. And click on Bundles

If you do not have this option in your MCF Shipping app, the store may not have enabled this option when setting up the app. As this is a add-on feature. To check this or change this. Click on ‘Account’ in the app.

You will be brought to step 1 of 3, in the app installation step. The first page’s title says ‘Add Your marketplaces’ you do not need to adjust anything on this page. Scroll down and press Next. So you can skip this step and move on to the next step.

Next you are on Step 2 of 3 and that page is titled Marketplace Add ons. Be mindful if you have multiple marketplaces. You will want to enable this feature in all of the marketplaces that you are allowing product bundles!

Scroll down to Orders and look at ‘Ship your Virtual bundles from Amazon’ This is an additional add on cost. And remember to activate this for each marketplace you need to process Amazon Virtual bundles. Make your changes, and price save, for each marketplace. And then press next!

Press next on the next page which is Step 3 of 3. Then, you will be sent to the ‘Coupon’ page. Press ‘Buy’ and then you will be sent to a Shopify payment page. As your subscription price may have increased. Approve those charges and you will be returned to the apps Home Page. Here you should see the ‘Bundles’ option!
The point of this step is to assign your virtual bundle SKUs with the SKUS of your real physical products.
This video goes over everything in detail.
If you’re looking for additional tools to help you optimize your Shopify store, then check out our Shopify store credit, which makes it easy to manage store credit.