Not everyone gets a refund. It mainly depends on how much income you have and how much tax withholding was taken out of your pay. The withholding is just an estimate to cover the tax on your income. If you don't have enough withheld then you end up owing on your tax return.
Your total income is added up. Then you get to subtract a Standard Deduction (everyone gets) giving you the Taxable Income. Then the Tax is calculated. Then the withholding and any credits you qualify for are subtracted from the Tax. Leaving you with a tax due or refund.
