Help me understand payroll tax levies

How is this garnishment typically imposed on a person? Is it a set amount that must be taken out of each paycheck until it the amount is repaid? Can this amount change/flucuate throughout the year, or should it be fairly standard (either in $ or %). Would the garnishment details specify from what paychecks it should be taken (i.e. normal paychecks vs off-cycle, such as a bonus).

Thanks in advance for any insight....reviewing a business unit's payroll and came across a few. One of them is of the actual payroll manager. Not only is there a tax levy, but they have 3 401k loans that they are repaying monthly. Given their role, I kinda consider this person a high risk of potential misappropriation in the future.