Do you mean you are doing three tax returns for three different people? Are you using desktop (CD/download) software or are you using online software?
If you are using the CD/download software, you go to File and click New Return each time you need to start a different return for a different person. Make sure each return is saved with a name that will allow you to know who it is for.
If you are using online TurboTax, you only get one return per fee. Each return needs its own account and user ID. If you use the same account and user ID for two returns, the second one overwrites the first one and it is gone forever.
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-onli...
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