@QKbookkeepingservices 

I pointed out (in a topic you started yesterday) that you are Lost on the Internet, asking Payroll in an income tax preparer forum. I also provided the link to the QB Community, and here it is again:

QB Community

So, not only is no one being rude, but everyone is trying to help you, and getting to the right resource would be part of that help. You are asking the wrong community, because nothing supports QuickBooks users. That's why Intuit doesn't mix Mint and QB and EasyACCT and Lacerte = different functions and uses.

As for your issue, give the client a W4 Worksheet. They might have other personal issues that matter, because the W4 is trying to take into account Payroll. But withholding is to help against their entire tax liability, and they can either add Estimate Payments or increase their Withholding, but only they will know their entire financial picture.

No one on the internet can help with this.