help, the income statement does not reflect the cost of sales; it has a value of 0.

Thank you for reaching out, @danhy1994. The Cost of Sales (COS) is calculated in QuickBooks Online (QBO) when a cost is assigned to the item. 

Since the COS is showing as 0 value, ensure a purchase cost is added to the item. Follow these steps:

1. Click the Gear icon and select Products and Services.
2. Locate the item in the list and click Edit.
   
   
3. Scroll down to the Purchasing information section.
4. Enter the cost of the item in the Purchase cost field.
   
   
5. Save your changes.

Once you've entered the cost of the item, revisit your Income Statement Report. You should now see the Cost of Sales reflected accurately.

However, if the values still show 0. You'll also want to check that the Report period is filtered to the correct one when running the report.
 

If you have any more questions, please don't hesitate to reach back out. I'm always a comment away.