If you used desktop software downloaded/installed from a CD to your own computer, then the tax files are stored locally on your own hard drive or any backup device you used like a flash drive. They are not stored online. If you cannot recover them due to a hard drive failure, etc. you can get a free transcript from the IRS or for a fee of $50, an actual copy of the return.
https://www.irs.gov/individuals/get-transcript
Contact your state for copies of previous state returns.
https://ttlc.intuit.com/questions/1901670-how-do-i-contact-my-state-department-of-revenue
Search your entire computer system (and any external storage) for the tax data file which ends in the *.tax2017 extension.
You appear to be using a Mac. See this FAQ on how to search for the data file.
<a rel="nofollow" target="_blank" href="https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac">https://ttlc.intuit.com/questions/1901659-find-your-tax-data-file-in-mac</a>
Also search for any PDFs you made.