Hi, I want to fill my 2014 tax which was missed. I do not know how to change the year from 2018 to 2014

[xmasbaby0]

You cannot do that!  The current online software is only for a 2018 return.  You cannot change the year and use it to file a 2014 return.  It is too late to use TurboTax to prepare and file a 2014 return.  The 2014 software has been retired.  It is also too late to receive a tax refund for 2014--the statute of limitations is over and any refund for 2014 has been forfeited.  But if you owe, the IRS still wants you to pay.

You can get the forms from the IRS and prepare them by hand and mail them in.

https://www.irs.gov/forms-pubs/prior-year