I am not getting the option to enter an IRA to Roth conversion for my spouse. What check box am I missing?

The first step to entering a Traditional IRA to Roth IRA conversion is to enter the Form 1099-R that is reporting the distribution from your spouse's Traditional IRA.  The follow-up questions after entering the Form 1099-R will indicate what was done with the money from the distribution.  That is how you indicate that it was converted to a Roth IRA.  

Be sure to indicate whose Form 1099-R you are entering if you have more than to enter.