In addition to the primary SKU, you can specify multiple alternative SKUs for each product.
Use this feature to store SKU's from other systems, barcodes, and other identifiers.
Alternative SKUs are used to match products when importing sales orders from other systems. If a product cannot be matched by its primary SKU, the system will attempt to match using alternative SKUs.
Enabling Alternative SKUs
To display and edit alternative SKUs, enable the Alternative Product SKUs option in settings.
Editing Alternative SKUs
When editing a product, click the Plus icon in the SKU field.

This will open a dialog where you can add alternative SKUs. For each SKU, you can also specify a label to help distinguish between different SKUs.

After saving, a dropdown arrow will appear next to the primary SKU in the product details. Click it to view all alternative SKUs for that product.

Bulk Editing Alternative SKUs
To update alternative SKUs for multiple products at once, use the bulk edit products in Excel feature.