Yes you can export tracking number from Acumatica to BigCommerce/Shopify. To do so you nee to put tracking numbers in the line with box under Packages Tab.
Keep in mind following rules: When shipments that include multiple boxes with separate tracking numbers are exported from Acumatica ERP to BigCommerce or Shopify, the system checks if the following conditions are met:
• Each item in the shipment is linked with a particular box. If an item is not assigned to any box, the system displays an error.
• Each box in the shipment contains at least one item. If a box is not assigned at least one item, the system displays an error.
During the synchronization of shipments with Shopify or BigCommerce, for each box in the shipment, a separate shipment with a separate tracking number is created in the online store. Boxes that don't have any items assigned or are missing a tracking number are not exported to the online store.