I've got you covered, @tcwrd_21.
Since the paycheck was already processed and cashed, you can consider adding the employee's retirement deduction on the next paycheck. If you need more guidance creating a paycheck, feel free to check out this article: Create paychecks to pay your employees.
You might also want to run a summary payroll report on QuickBooks Desktop. This way, you can review all your payroll totals, including employee taxes and contributions.
Our doors are always open to help you again if you need further assistance running payroll in QuickBooks Desktop. Wishing you all the best, @tcwrd_21.