Hi hossam1,

To enable the tax column to appear on your invoices in QuickBooks Online (QBO), you’ll need to set up a tax rate through the sales tax center.

If you haven’t set up a tax rate yet, follow these steps:

1. Navigate to Taxes.
   
2. Click on Set up tax.
3. Enter the required details, such as the Tax name, Tax agency, Sales rate, etc.
   
   

Once the setup is complete, you’ll be able to add taxes to individual line items on your invoices.

You can always ask for help in the Community if you need anything else.