Why can’t I access my 2018 tax documents

[VolvoGirl]

You need to register a 2019 online account to access prior years
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-access-my-prior-year-return/01/270...

That's common to end up with multiple accounts. First LOG OUT of whatever TurboTax account you're logged into right now. Then use this TurboTax account recovery website to get a list of user ID's for an email address. Run the tool against any email addresses you may have used
https://myturbotax.intuit.com/account-recovery/

If you used the Desktop CD/Download program then the only copy is on your computer and not saved or stored online.

[mirela]

I need the spread sheet with the calculations of our rental home depreciation for the taxes we did last year on line with TurboTax business

[DaraLO]

@mirela You can download your prior-year tax return, including all schedules and forms.  Refer to the following TurboTax FAQ for instructions:  How do I access a prior year return? - Community