How do I update my name change

Depends on whether you have already filed 2018 or not:

1) if you filed 2018 taxes earlier this year, with your former name, and that tax file was accepted and processed.....then you just need to make sure your new name has been registered with the Social Security Administration already..or ASAP,and then you will use your new name when you file 2019 taxes next Feb-April of 2020.

2) if you have not yet filed 2018 taxes, and are still preparing them now...then, in the Online software, you change the name in the My Info section after you get back into your tax file.    However  if the name change was really recent, and you have not filed 2018 yet...the IRS may still have your former name on their computers (it takes a month, or 3, for the SS name change to get to the IRS computers) and you may need to continue to use that to file 2018 taxes.  IF e-filing doesn't go thru, you may end up having to print and mail-filing yourself no matter which name you use.