How can I add inventory widget to form with multiple products to have maximum of 10 units sold please?

How can I add inventory widget to form with multiple products to have maximum of 10 units sold please?

It seems like you need to limit the available quantities for existing products of your form; however, that it's not possible to achieve with the widget and the payment settings do not have such option available either. 

You will need to add the widget to your form and configure it from scratch, please find the widget here: https://widgets.jotform.com/widget/inventory 

These guides will help you adding the widget to your form, performing calculations and passing the result to the payment field: 

https://www.jotform.com/help/252-How-to-Add-a-Widget-to-Your-Form 

https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget 

https://www.jotform.com/help/275-How-to-Pass-a-Calculation-to-a-Payment-Field 

I hope this helps.