Not quite sure what you are trying to ask about--or what tax year you are referring to. Your W-4 is used to tell your employer how much to withhold from your paychecks. It does not dictate how you have to file your tax return. When you prepare your tax return, you enter the correct number of dependents, and your correct filing status (single, married, head of household, etc.). If you have not had enough tax withheld, you may end up owing tax to the IRS when you prepare your return. If you have had enough, or more than enough tax withheld, then you may receive a refund when you file your return.
If you need to change it, you can prepare a new W-4 for your employer.
https://turbotax.intuit.com/tax-tools/calculators/w4/
https://www.irs.gov/individuals/tax-withholding-estimator
https://www.irs.gov/pub/irs-pdf/fw4.pdf