I filed my 2018 taxes, but since recived a W-2 from a company that I worked for during 2018. I did not have this w-2 in my possession at the time that I saw my tax person. And she filed my taxes and t

It might be the cheapest and easiest to go back to your tax lady to amend 2018. if you did do your amended return using TurboTax you would have to:

a.) purchase the desktop 2018 software. online preparation is only for 2019 returns. if your state has an income tax the state return would have to be purchased as an addon; 

b.) enter all the 2018 data from scratch though in some case summary totals could be used - like for itemized deductions and then make sure all the numbers agreed with the original return; 

c.) save it then open by clicking on amend. add the w-2 and enter any refund you received or any balance due payment you made;  

d.) file your amended return by mail since it can not be e-filed.  follow TT's filing instructions.  

can't say whether you will owe or not. that depends on the withholding as compared to the increase in your income tax.  if you owe include payment. the taxing authorities will bill you for any penalties and interest. There are no penalties or interest if you'll be getting a refund.  

it might take the taxing authorties many months to issuue you a bill for any penalties or interest if you owe.

mail returns by a method where you get proof of delivery