When does access to the prior year returns end :

https://ttlc.intuit.com/questions/3355524-when-does-access-to-my-prior-year-turbotax-online-returns-...

 Access to prior year returns are locked:

https://ttlc.intuit.com/questions/3404575-how-do-i-access-my-prior-year-2017-return

You can get a free transcript from the IRS:   

https://www.irs.gov/individuals/get-transcript

How do I get a copy of a return I filed using online TurboTax?

https://ttlc.intuit.com/questions/1900748

How do I get a copy of a return I prepared using desktop TurboTax?

https://ttlc.intuit.com/questions/1900639

Note:  Every year, before mid-October, print a copy of your current year tax return and save it as a tax file and PDF, too.  That way you will have it when you need it for school, a loan, next year’s tax return, etc. without going through a lot of aggravation (and expense)  to get it.

Save as tax file :

https://ttlc.intuit.com/questions/1899645-how-do-i-save-my-2018-turbotax-online-return-as-a-tax-data...