If you are using the Desktop version (which you install on your own computer) simply open/launch the program and select the BLUE "Start a New Return" button (or select "New Return" under the "File" tab in the menu bar) near the center of the window; TTax should then save each return with a unique filename based on the first name listed on the actual return.  Multiple returns are no problem and no additional cost. The IRS limits you to 5 e-filed returns; however you can print and mail additional returns. 

Thanks! And I can import her 2018 return and it won't overwrite my 2019, right?