How to file self employed quarterly taxes? where on the TurboTax app can you file quarterly taxes?

TurboTax can help you calculate and print out forms 1040-ES so you can mail in your estimated payments. See:

• Can TurboTax calculate next year's federal estimated taxes? 
• If you need to do estimated state income tax payments, see Can TurboTax calculate the estimated payments for next year's state taxes?

The postmark date is used to determine if the estimated tax payment is paid on time. Additional payment options are available at the IRS Payment website 

Taxes are pay-as-you-go. This means that you need to pay most of your tax during the year, as you receive income, rather than paying at the end of the year.