Shopify locations are places where you stock inventory, fulfill orders and sell products.
The inventory location which you configure in the Connectr app will be assigned as the default location for all the products imported from Amazon.
If you want to automate fulfilling orders via Shopify's 'Fulfillment by Amazon' Service then set location to 'Amazon Marketplace Web'. In this case, The inventory for FBA products on Shopify will be managed by Amazon. There have been multiple cases where the inventory has not been updated correctly. Shopify provides minimal support for queries, and troubleshooting inventory relates issues. Connectr app cannot update inventory for such products because it gets overwritten by Amazon service. We do not recommend this method.
Secondly, if you want to fulfill orders via FBA using the Connectr app's 'Ship by FBA' functionality, we strongly recommend you do not set the default location to the 'Amazon Marketplace Web'. Keeping the default location to 'Amazon Marketplace Web' prevents the app from updating Shopify orders.
More information about fulfilling orders available here.