My return is asking for a box 20 input but there is nothing there, it keeps asking for a locality name. What does that mean

If you click in the box, you'll get a drop down menu.  It wants your county so it will list all of the counties in your state.  Just choose what county you're filing from.  I got the same message as an error when it ran an error check.

It is a local tax that some employees have to pay depending on where they live and work.  Is there any amount in Box 19?  If not, that means no local taxes were paid and you can leave boxes 18-20 all blank. 

If there is an amount in Box 19, ask your employer for a corrected W-2 showing which locality the taxes were paid to.