Understand what Workday actually has in place of a product catalogue — spend categories, purchase items and supplier items — then learn D365's full product data model from first principles, including the critical distinction that Worktags are financial dimensions, not product dimensions.
Workday Financial Management is not an inventory or product management system. It does not have a product master, product variants, item model groups, or storage dimension groups.
Spend Category is a typed Worktag — a named classification of expenditure. Every purchase requisition line and purchase order line carries a Spend Category Worktag that classifies what is being bought: "Software Licences", "Consulting Services", "Office Equipment", "Travel".
A Workday practitioner who hears "financial dimensions" and "product dimensions" in the same D365 overview often assumes they are two views of the same concept. They are not.
For most Workday customers, this is not a migration — it is a design. The following concepts must be understood and configured before any Purchase Items are loaded.
Workday's product data surface — Spend Categories, Purchase Items, Supplier Items — is a procurement catalogue, not a product management system. The migration from Workday to D365 requires building the D365 product data model from first principles.