If you have prepared your prior tax returns with Sprintax, they are available to download from your account.
However in case you have used another service, you may need to contact them for a copy.
Alternatively you can request a transcript from the IRS and State tax offices from their websites.
You can find the Federal transcripts here.
And you can search specifically for each State tax office by using 'State tax office+ transcript'
Example: NY tax office transcript