Hello @khaled2,
Welcome to the Community. I can share some information about the QuickBooks mobile app.
Currently, the features and options you can use in the mobile app are limited only. As a workaround, I recommend accessing your account using the mobile web browser.
This way, you'll be able to add the initial quantity on hand to your products and services. Please know that I appreciate your input on this feature, and this preference might be available in the future.
Additionally, I've attached an article you can use to customise invoices using the mobile app: Customise invoices on the QuickBooks Online mobile app.
Leave a comment below if you have other concerns. The Community and I will be around to help you.
