If your 2017 tax return showed that you owed tax, you may need to make some changes in 2018 to ensure you won't owe again next year.
If you are an employee, you can have more taxes withheld from your salary. Do this by filing a new Form W-4, Employee’s Withholding Allowance Certificate, with your employer.
If you have income that is not subject to withholding (such as dividends, interest, or earnings from your business), you may need to make estimated tax payments in 2018. As long as your 2018 estimated tax payments equal at least 100% of the tax shown on your 2017 tax return, you will avoid an underpayment penalty in 2018. If on your 2017 tax return you owed less than $1,000, you are not obligated to make estimated tax payments in 2018.
If you can't pay the 2017 taxes owed, you can file Form 9465, Installment Agreement Request, to set up installment payments with the IRS and pay the tax due in installments for up to 72 months.