Thank you for posting here in the Community. Allow me to assist you with the information you need related to the QuickBooks Online product.
The ability to acquire the USA Corporate office phone number in this public space is unavailable. You'll need to go through the normal process of contacting QuickBooks Support within your account.
They'll be able to assist you further with any issues that require account verification. Please also know that you can share with us what help you need as we can offer assistance in the Community. For the Worldwide Office Locations and phone numbers, here's the link: https://www.intuit.com/company/locations/.
In case you need the steps on how to contact support, please follow these steps: