In order to activate payroll in Quickbooks, the desktop one has to have the service key with only then it can be activated. The steps which you must follow are:
[ul]
[li]First, select Employees and then click on Payroll and choose the option of Install Payroll[/li]
[li]You need to complete all the fields that are in Payroll License and Product Information page. The license number and product number are found in the folder inside the box work together to produce service keys that can unlock payroll subscription[/li]
[li]Now enter the service key and complete all the fields in the Payroll Company Legal Information section[/li]
[li]Then a confirmation will appear that says payroll service is activated[/li]
[li]And select finish to complete the activation process[/li]
[/ul]
If you find any difficulty while activating the payroll service you are requested to dial  Quickbooks Customer support phone numbers  where professionals are there to resolve the issue faced by their clients.

For technical assistance click below:
Quickbooks Contact Number