The Mixtable spreadsheet interface is a great tool to quickly enable inventory tracking for multiple Shopify products at once and to enable tracking across multiple locations. There are two ways to accomplish this.
Note: Inventory in Shopify is stored against variants, not against the parent products. So for all the steps above you need to be working in a Products - Complete (with Variants) worksheet where each row represents a variant in Shopify. Keep in mind that by default, Shopify always creates a variant for a product.
If inventory tracking is not currently enabled for one or more of your products, the simplest way to enable this tracking is to set an inventory value for a particular variant at a particular location. When you initiate the sync from Mixtable to Shopify, if inventory tracking is not enabled for the given variant at the given location, Mixtable will automatically turn inventory tracking on and after that is done it will set the inventory level to the value you’ve given us.
The second way to enable inventory tracking to be done by Shopify is to set the inventory management field to have a value of “shopify” for a given variant. If inventory management is set to “shopify”, that instructs Shopify to track inventory for that variant. If the inventory management value is not set to “shopify”, then Shopify will not track inventory for the given variant.