You need to create a separate tax return if you want to file for some one else.

Please see link below for more info:

https://ttlc.intuit.com/questions/1894512-how-do-i-start-another-return-in-turbotax-online

Thanks for using TurboTax!

Online is only good for 1 return.  But you can use the same email address for 5 accounts.   How to start another return in the Online version https://ttlc.intuit.com/replies/3288574 

How do I file for my sisters 1099R with TURBO TAX under $40,000.

Are you using the Desktop CD/Download program or the online version?

Online is only good for 1 return per account.  But you can use the same email address for 5 accounts.   How to start another return in the Online version

https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-onli...

The Desktop CD/Download program can do unlimited returns.

There are 2 different Free online versions.  Turbo Tax Free Edition and the IRS Free File website.  If you don't qualify for the Free Edition  you might qualify for the Free File website.

There is also The Turbo Tax Free File program which is free for federal and state.  And has more forms than the Federal Free Edition, like Schedules A, B, C , D, E, F, EIC, H, K-1, SE,  etc.

To qualify for the Free File website  you just need to meet one of these 3 things.

AGI $39,000 or less.

Active duty military with AGI of $72,000 or less

OR qualify for EIC (earned income credit.)

In order to use the Free File program, you have to start it at a special website.  Click on Sign in at the top right.  It may let you continue your return so you don't have to start over.

https://freefile.intuit.com/