There are five ways you can make estimated tax payments:
You can credit any overpayment from last year’s return to this year’s estimated taxes. You do this by indicating on the return that you filed for last year that you want the overpayment credited to this year’s taxes, instead of receiving a refund. The credit is then applied to your estimated payments this year in the order necessary in order to avoid an underpayment penalty.
You can use the payment vouchers from Form 1040-ES (available on the IRS website) and send your estimated tax payments by mail.
You can use the Electronic Federal Tax Payment System (EFTPS) and make your payments either online or by telephone.
When you file your return for last year by Internet, you can authorize and schedule electronic funds withdrawals from your bank account for your estimated tax payments for this year.
You can make payments by credit card, using one of the service providers indicated in the Form 1040-ES instructions or in Publication 505.
How Are Estimated Payments Reported on the Tax Return?
Estimated tax payments are reported in the Payments section of Form 1040 or 1040A when you file your annual tax return. You should include any overpayment from the prior year that you applied to the current year estimated tax.
Married Taxpayers
If you and your spouse paid joint estimated tax but are now filing separate income tax returns, you can divide the amount paid in any way you choose as long as you both agree.
If you cannot agree, you must divide the payments in proportion to each spouse's individual tax as shown on your separate returns for the current year. If you or your spouse paid separate estimated tax but you are now filing a joint return, add the amounts you each paid.
Divorced Taxpayers
If you get divorced in the current year and you made joint estimated tax payments with your former spouse, either spouse can claim all or part of the joint payments. If you cannot agree, you must divide the joint payments in proportion to each spouse’s individual tax as reported on your separate returns for this year.
If you are claiming a portion of a joint payment on your separate return, you should put your former spouse's social security number in the space provided on the front of Form 1040 or 1040A. If you were divorced and remarried in the current year, you should put your present spouse's social security number in the space provided on the front of Form 1040 or 1040A, and then in the Payments section, to the left of the estimated tax payments line, you should write your former spouse's social security number, followed by "DIV".