How can I add student loan repayment for an employee who started in October?

That's okay, Lindag. I hope you enjoyed your Christmas celebration.

Let's go over to your concern. Repayments are not taxed. Let me help you set it up.

Here's how:

1. Click Employees, then go to the Employees tab.
2. Select the employee to open their profile.
3. Click Actions, then select Deductions.
4. In the Loan repayment section, click Add.
5. Enter a desired name, then select the Rate type.
6. Enter the default value or default percent. 
7. Click Save.

When you create a paycheck, the deduction will show.

Here's how it looks like:

I'll include the article on how to add or customise deductions in QuickBooks Standard Online Payroll.

I'm just around if you need my help. Just tag me and I'll get back to you as soon as I can.