How do I sign in to direct pay to make my quarterly payment today?

[VolvoGirl]

Pay directly at the IRS at https://www.irs.gov/payments 

You will have to go to your state website and find their pay screen.

[DoninGA]

Go to this IRS website for using Direct Pay - https://www.irs.gov/payments/direct-pay

After entering the type of payment you will be making the IRS website will require this -

Verify Identity

Direct Pay verifies your identity using information from your 1040 filing history. Please provide the following information from a 1040 tax return you filed during the previous six years.

Note: the Tax Year for Verification you enter here does not have to match the tax year for your payment.