There is only one file type that uses the .T16 extension:
H&R Block 2016 Tax Return
A T16 file is a tax return created by the 2016 version of H&R Block Tax Software. It contains U.S. federal tax forms, any necessary state tax forms for 2016, and personal tax information entered by the user.
MyTaxes.t16 - Default filename given to H&R Block 2016 tax return files, although you can rename the file.
|H&R Block Tax Software||Commercial|
Updated: January 31, 2017