How to Access prior year online returns
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/00/27010
If you can't get the side menus to open up to access the prior year..... You need to start entering some basic Personal Info in 2022 for the side menu to open up. Just continue a little ways into 2022. I had to go though about 12 screens.
If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online. So you need to make and keep your own backups.
Or request a transcript from the IRS
https://www.irs.gov/individuals/get-transcript
Not sure what you mean by "all" of your tax returns. TurboTax and the IRS save your returns for seven years. Returns older than seven years are gone. If you mean more recent than seven years ago, use the links provided by VolvoGirl.
If you used the CD/download to prepare your returns, they are not stored online. They are stored locally on the hard drive of the computer that you used or on any back up device that you used.