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.

Here's how:

1. In QBO, go to the Gear icon at the top to get to the Products and services. 
2. Click on Edit on an existing item or select New at the upper-right. 
3. Enter the SKU.
4. Hit Save and close.

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!