To enter, edit or delete an IRA contribution -
Click on Federal Taxes (Personal using Home and Business)
Click on Deductions and Credits
Click on I'll choose what I work on (if shown)
Scroll down to Retirement and Investments
On Traditional and Roth IRA Contributions, click the start or update button
Or enter ira contributions in the Search box located in the upper right of the program screen. Click on Jump to ira contributions
You can enter your traditional IRA contributions to either take a deduction, or track your basis if your income is too high to take a deduction.
Here is how to do this in TurboTax Online:
Here is some more information about IRAs: Deductions Allowed for Contributions to a Traditional IRA