To view what tax payments have been accounted for so far, go to:
My Account (top menu) > Tools > View Tax Summary and look for Total Payments
To enter estimated 2016 taxes that you previously paid to the IRS:
Click Federal Taxes (top menu)
Click Deductions & Credits (just below top menu)
Scroll down to Estimates and Other Taxes Paid and click Show More
Click Start next to Estimates
