how we can Connect the Accounting system to Zatca Portal for E-Invoicing?

Welcome to the Community, Asma. 

QuickBooks Online (QBO) does not have a direct integration with the ZATCA portal for e-invoicing. However, you can explore third-party applications to meet compliance requirements.
 

To find and add accredited apps within QBO, here’s how:
 

1. Go to the Apps menu.

2. Select Find Apps.

3. Use the Search bar to look for an app, or scan them in the Browse categories or industries.
 

If you need further assistance, feel free to let us know in the comments below.