Get your taxes done using TurboTax

It goes by your date of birth you entered under My Info or Personal Info. If you or your spouse is 65 or older you will automatically get the 1040SR even if it shows the regular 1040 on the screen.

In the Online version it will probably show the regular 1040 on the screen but if you print it out or save the pdf it will be the 1040-SR.