How do l file a amended state tax for 2015? ONLY the STATE TAXES

TurboTax does not support tax year 2015.

Go to your state department of revenue website and you can get a prior year state tax form.

See this TurboTax support FAQ for state department of revenue contacts - https://ttlc.intuit.com/community/state-taxes/help/how-do-i-contact-my-state-department-of-revenue/01/25573

If you never filed a 2015 state tax return you do not amend the return, you file the original 2015 tax return.

Note - If filing for a tax refund the time to file has expired.  Most states have a three year limit to file for a refund from the original due date of the tax return.  For tax year 2015 the state tax return with a refund had to be filed on or before April 15, 2019.

There is no time limit if you have taxes owed.

Turbo Tax doesn't support 2015 or prior anymore.  You will have to get the blank forms from your state website and fill them out yourself or go to a local tax place or accountant.