I can’t tell which version of TurboTax you’re using, but try clicking the Take me to my return or Pick up where you left off button. This should populate the left pane, which has the Tax Tools dropdown.
The deferral is part of new legislation that allows self-employed taxpayers to pay only 50% of Social Security tax on net earnings from self-employment for the period March 27, 2020 through December 31, 2020 this year, and the other 50% next year.
