When you first start work, you'll be asked to fill out a Form W-4. This form helps your employer figure out how much money to withhold from your paycheck for federal taxes. The amount can differ, depending on how much you earn and how you fill out the form. Relax! The form comes with an easy worksheet you can follow that asks a bunch of questions: stuff like whether you're married or single, whether you have children or not, and whether your parents can still claim you as a dependent.
Your answers to these questions will help your employer calculate how much tax money should be deducted from each paycheck. The idea is to deduct just the right amount of money from each paycheck, so you will avoid having to pay one big tax bill at the end of the year.