Box 15. I have the state taxable amount in that box and in the program it asks for local tax withheld. what do I do ?

You should report your W2 as provided.

Local is not your state, it is your city/county.

Box 15 is for state taxes, Box 16 reports state income, Box 17 reports state tax.

Boxes 18-20 reports local income and taxes. However, these may be blank if there is no local income tax.