Welcome and thanks for posting in the Community, @userck-tang.
In QuickBooks Online (QBO), the option to enable barcodes is currently unavailable. However, you can use the SKU feature to help track your inventory items as a workaround.
To learn more about managing inventory in QuickBooks Online (QBO), check out this article: Add inventory products.
You can also run reports to keep track of your inventory. Refer to this article for more information: Use reports to see your sales and inventory status.
In the meantime, I recommend visiting our Blog site. This is where we share recent happenings and future developments, such as updates to newly added features. Here's the link: https://quickbooks.intuit.com/blog/.
Please let me know if you have any other issues or concerns in the comment section below. I'm always here to help. Have a great day!