Can I know how add app on desktop?

Hello, emad.

I can see the convenience of having the QuickBooks Online (QBO) Desktop app on your computer. Let me share some helpful insight about your concern.

The QBO Desktop app is only available in the United States (US) and Canada version. If you want to install the QBO Desktop using the global version, then it's unavailable.

In the meantime, you can add a QuickBooks Online shortcut or icon to your desktop as a workaround. I'll provide a few steps to get this done for all browsers, whether you use a Windows PC or Mac.

Here's how:

1. Close or minimise any open windows.
2. Open the browser you commonly use QuickBooks Online with.
3. Also, make sure to have it on window mode so you can still see your desktop screen.
4. Sign in to your QuickBooks Online account.
5. Drag and drop the View site information icon (beside the web address) onto your desktop screen. 
6. Then, you may see a lock icon, and it depends on the browser you use.

Once done, you can use the shortcut you created to open QuickBooks Online from your desktop screen and continue with the tasks. See this article for future reference: Get started with QuickBooks Online.

Keep me posted if you have clarification on managing your QuickBooks account. I'll always be here to help you.