I am using the system for a UAE company. Under Account and Settings I cannot see Payments I need to set up Pay Now in invoices. How can I do that?

Welcome to the Community, @hadi2.

Processing customer payments for online invoices is currently available in the US version of QuickBooks Online (QBO). Since you're using the UEA version of QBO, it's the reason why the Payments option isn't showing in the Account and Settings menu.

As a workaround, you can consider looking for a third-party application that integrates with QBO to process customer payments online.

Just in case you need to know how to process customer payments outside of QuickBooks, feel free to read this article here for more guidance.

If you need any assistance processing customer payments in QBO, I'm available here to help any time!

@hadi2 

What kind of business do you run? You may need a 3rd party app as a workaround to accept online payment.