Where are order-time custom field values stored?

The values a customer enters for an order-field-set at checkout are stored on the order line (in a custom-fields payload on the line, CustomFieldsJson), so each purchased line carries its own captured answers. This keeps order-time custom data tied precisely to the specific item it concerns — the engraving text travels with the engraved item's line, the appointment preference with the…

The values a customer enters for an order-field-set at checkout are stored on the order line (in a custom-fields payload on the line, CustomFieldsJson), so each purchased line carries its own captured answers. This keeps order-time custom data tied precisely to the specific item it concerns — the engraving text travels with the engraved item's line, the appointment preference with the service line — and is available wherever that order line is viewed or processed (fulfilment, documents, support). The cart captures the same values as items are added, then they're snapshotted onto the order line at checkout.