Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
You will find a list of support telephone numbers at https://support.microsoft.com/en-us/help/4051701/global-customer-service-phone-numbers.
There is also a chat: https://support.microsoft.com/en-us/contactus/.
I don't know if there is a specific contact for installation and activation.