Yes, there is no prohibition on contributing to a spousal IRA for your spouse just because they are already retired. You must meet the requirements for being able to contribute to a IRA at all, including age, income and whether you are covered by a retirement plan at work. TurboTax will ask all the questions to determine your eligibility.
Please see our TurboTax blog article Am
I eligible to make an IRA contribution? for more information.