My accountant extended my return, how do i mark in turbo tax?

Are you using Turbo Tax to file?  Just file as normal.  If you made a payment  be sure to enter it.

To enter the amount you paid with an extension (including state extension)  go to

Federal Taxes (or Personal for desktop H&B version)

Deductions and Credits

Then scroll way down to Estimates and Other Taxes Paid

Other Income Taxes - Click the Start or Update button

Next page second section Payments with Extension

Either Visit All or Click Start or Update by the extension you paid

if no "payment with request" was made, there is no mark.

IRS knows you have an extension of time.

@herbiesilverman