In the W-2 section of the Federal Q&A, you can enter information for Boxes 15-20. In Box 20 (Local Name), you can only select "Indiana Locality" (which will appear as "IN" on the form) for the Indiana locality. The actual locality name needs to be entered in the Indiana State Q&A.
To enter the locality in TaxAct® (after entering your W-2 information in the Federal Q&A):