Yes, you can file your 2018 tax return using TurboTax.  The TurboTax 2018 programs are available at this site File your 2018 taxes.

how do I get a link to file Turbo Taz 2018.. Yesterday I did my 2019 on Turbo... website keeps going back to what I owe page when I login??? 

The online software is available for the current tax year only. As tax law changes from year-to-year, it is important that you complete your taxes in the proper version of the software. To complete a prior year return, you will have to purchase and download software for the applicable year. Be sure you are using a device in which you can download, such as a laptop. See the link below to purchase:

TurboTax Prior Year Products

I would like to file my 2018 tax return now

@happygilmore6697

You can file your Tax Year 2018 return using TurboTax.  Please see File your 2018 taxes for guidance.

Now with the stimulus checks going out in a few weeks.  Can I add my direct Deposit info so the stimulus ck doesn't get mailed.. 

The Care Act was just signed on 03/28/2020, and we have not gotten any guidance regarding the distribution of checks.  If you've already filed your 2019 tax return, it will be processed based on the method of payment you chose. 

If you wish to change it for the future payment we will have to wait for additional information.  I do expect that there will be a procedure to adjust mailing addresses and bank accounts.