I am trying to apply for OAS supplement but can not find my T1's for previous years that I stored on my computer, can anybody help?

If you stored any PDF from TurboTax return form previous years- you should be able to type in on the bottom of your computer screen in search- TT.16 and it should come up if it was saved.

https://turbotax.community.intuit.ca/replies/2648026