Here's how each Magento data structure should typically map onto Shopify, and why:
A configurable attribute that the customer must select to complete a purchase — size, color, pack size — should become a Shopify product variant. That's the core rule: if it's a purchase choice, it's a variant, not a metafield.
Where a Magento configurable product's attribute combinations (its catalog_product_super_attribute data) exceed 3 option dimensions, it can't be migrated as a single Shopify product as-is, because Shopify enforces a hard ceiling of 3 options and 2,048 variants per product. These need to become split products linked via combined listings, or be handled through a third-party options app instead.
A product-specific structured attribute — material, dimensions, ingredients, usage instructions — is informational rather than a purchase choice, and is specific to a single product. This should become a Shopify metafield, defined with a clear namespace and key rather than dumped into the description.
Reusable structured content shared across many products — certifications, size charts, ingredient glossaries, compliance documents — should become a metaobject instead of a metafield. The distinguishing factor is that the same content is referenced by multiple products and should be maintained in one place, not duplicated per product.
Magento's customer_group logic, which determines pricing and access visibility rather than product selection, should map to Shopify B2B / Company locations (on Plus) or customer tags, not to variants or metafields at all.
Finally, Magento's sales_order_status_history should be preserved as order timeline notes or order metafields — this keeps the audit trail intact without re-triggering customer-facing notifications for historical events.
If your catalog has deep attribute sets and layered navigation, this mapping decision is the highest-leverage part of the whole project — get it wrong and you're re-architecting metafields post-launch across the entire catalog. If your store falls into this category, this is exactly the kind of structured planning our Magento to Shopify migration service is built around.