"I claim zero all year but was told I should’ve put 1"
If you're referring to the W-4 here, you're mixing oranges with peanut butter. What you claim on your W-4 that you provide to your employer, has nothing to do with itemizing deductions. Regardless of what you claim on your W-4, if your itemized deductions do not exceed your standard deduction, then itemizing is not best for you tax-wise. Taking the standard deduction would be best for you.
What you claim on the W-4 is used by your employer, and only your employer, to determine how much tax to withhold from each of your paychecks. It has nothing to do with your "itemized" deductions.
