I need to transfer 2015 turbo tax file into 2018 software how can i do it

[VolvoGirl]

Sorry no.  You can only transfer from 2017.  Where is your 2017 return?  Did you file one?

https://ttlc.intuit.com/questions/1901506-transfer-last-year-s-return-to-2018-turbotax-for-windows