Hi there, ClaudiaWest.

It would be inconvenient for your client's employees to reach our Phone Support Team during the tax season. Instead, You can let your client send an email attaching this community post about the client ID on their W-2: https://quickbooks.intuit.com/community/Employees-and-payroll/Using-QBs-Online-to-prepare-W-2-There-....

If they have other questions, they are always welcome to post here in the Community. 

I'll be around if you have any additional questions about QuickBooks. Thanks.