Can I import ALU column from Quickbooks POS into Shopify for bulk tagging?

Where can I find a variant SKU field???

Does this make them scannable? I have found the 4-digit QB item number in the SKU field to be searchable but NOT scannable. I have also tried to make it 6-digits in the barcode field (so I can still search at least).

The QB migration team sends me to retail, and back and forth.