I need 2018 & 2019 Tax returns. Filed Married bur separately in 2018, filed joint in 2019. We opened a business in late 2019 and hired an accountant in 2020. Can't access

To access your prior year online tax returns sign onto the TurboTax website with the User ID you used to create the account - https://myturbotax.intuit.com/

Scroll down to the section Your tax returns & documents.  Click on the Year and Click on Download/print return (PDF)

If you used the desktop CD/Download editions installed on your computer, the only copy of your tax data file and any PDF's will be on the computer where the return was created.  TurboTax does not store online any returns completed using the desktop editions.

Or go to this IRS website for free federal tax return transcripts - https://www.irs.gov/individuals/get-transcript

For a fee of $43 you can get a complete federal tax return from the IRS by completing Form 4506 - http://www.irs.gov/pub/irs-pdf/f4506.pdf

only the iRS would have copies since you say prior to 2020 they weren't done with TurboTax and the only copies you had were destroyed. you can go online, register, and download transcripts https://sa.www4.irs.gov/secureaccess/ui/?TYPE=33554433&REALMOID=06-00008e4d-63f6-1187-a229-7c2b0ad00000&GUID=&SMAUTHREASON=0&METHOD=GET&SMAGENTNAME=-SM-u0ktItgVFneUJDzkQ7tjvLYXyclDooCJJ7%2bjXGjg3YC5id2x9riHE98hoVgd1BBv&TARGET=-SM-https%3a%2f%2fsa%2ewww4%2eirs%2egov%2ficce--core%2fload%2fgettrans%2fpages%2favailableTranscripts%2exhtml 

or you can mail in 4506-T for transcripts

https://www.irs.gov/pub/irs-pdf/f4506t.pdf 

or if you need an actual copy you can mail in form 4506. there is a fee of $43/return

https://www.irs.gov/pub/irs-pdf/f4506.pdf 

In some situations, if you file with Turbotax Online one year, and don't use a paid version of Turbotax in the next year, your access to your returns will be cut off unless you pay an extra fee.  However, the policy sometimes changes and I don't know the current rules.  Turbotax Online also doesn't retain returns indefinitely, only 3-4 years.

You would need to know which accounts you and your spouse used in 2019 (probably different user names and passwords than your joint account in 2020).  Sign in, see if the file is available, and what the cost is going to be.  Then you can try calling customer support and see if they will give you a break.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/turbotax-phone-number/L0Od33nMQ_US_en_US

If you used the program installed on your own computer, Turbotax does not retain copies online.

You can get copies or transcripts from the IRS as described, although I think they only go back 6 or 7 years.