Combo products can be offered through other sales channels. However, when a combo product is sold through another channel, it's not broken up into the items that are associated with the bundle. This is because there is no cart page for the customer to land on that allows this to happen. Instead, the singular combo product is passed through the checkout and attached to the order.
The combo product notes, on the order, which items are needed for fulfillment through your Shopify admin.
Note: This is not compatible with order fulfillment apps (ex: Oberlo, TradeGecko, etc.). The products selected by the customer are only placed as a note on the order. They do not come through to your Shopify admin as individual items. Orders with combo products, sold through another sales channel, would need to be fulfilled manually.
To make these orders stand out in your Shopify admin, they're tagged with “BUNDLES_COMBO_PRODUCT”. The inventory is then deducted from each product that was purchased in the bundle.
Bundle products that have a variant selection will use the default variant in stock for each of the products your customers select.
Note: Your customers are not able to select specific variants when offering combo products through other sales channels.