You don't "have" to. Permitted Roth contributions don't actually go on your tax return. The only information that goes to the IRS from your tax return is:
A/ A penalty for an unwithdrawn excess Roth contribution, based on limited earned income, being Married Filing Separately, too much contributions, or income above the Roth thresholds.
B/ You could get a Retirement Savings Credit if your income is low enough to support that. It cannot be calculated if your contribution is not inputted.
It is recommended that you inform Turbo Tax of the Roth contribution, so any consequences (good, bad, or none at all) can be addressed.