I'm entering a K-1 into Form 1120 using TurboTax Business 2023. Part III line 20 lists a Z * STMT. The drop down menu is missing "Z" as a choice, how do I enter this?

Form 1120 does not have a K-1 and Form 1120-S does not have a Line 20 on associated K-1s.

You must have been issued a K-1 (1065) which does have a Line 20 and there is a Code Z in the dropdown in TurboTax.