Do I need to fill “Form W-2 (City of New York): Box 15 employer ID-1 must be entered.”
 Because “Box 15” does not say employer ID-1, so what do I do?

I attached an attachment with a snapshot picture of what TurboTax Free Edition (Online) says. I live in New York City.

Get your taxes done using TurboTax

If there isn't an entry in box 15, put anything in the box to clear the error.

Get your taxes done using TurboTax

What to do if Form W-2 Box 15 says “NEW YORK” in it?

Get your taxes done using TurboTax

put anything in there that will clear the error.