I need to deduct an amount of money from multiple employee's wages for uniforms, how is this done? Do I need to set up a post tax deduction for each individual employee?

Welcome to the Community, josh93. 

Let me show you how to set up a deduction category in QuickBooks and apply it on a pay run. 

1. Go to Employees tab.
2. On Payroll Settings, select Deduction Categories. 
3. Select Add, and then enter the Name of the new deduction category. 
4. Select Deduction type and Classification.
5. Then click Save. 

Once done, you can set up a deduction for an employee which will automatically appear when you process a pay run. 

Here's how: 

1. Select Employees from the left-hand menu, then select the employee you wish to add the deduction to.
2. Select Pay Run Inclusions from the left-hand menu, then select the Add button next to Deductions. 
3. Select the Deduction Type and Amount.  
4. Select the method This deduction should be paid.
5. Enter any other relevant fields (including start and end dates), then select Save.

Also, you can check on these article for more detailed information. 

Set up employee deductions

Update deduction categories for STP Phase 2

Let me know if you need any help by leaving a comment below. Have a nice day!