How can i reprint my 2018 tax returns with turbo tax mailing instructions?

Please log back in your TurboTax account and "add a state" to open the return back up (you are not really adding a state, just to open it back up), then select Tools on the left, Print Center and choose the print center, then select returns and choose to print just the tax return or to include all worksheets as well.

How can I do this now in 2021 given the online software for 2018 is gone?

If you need to file your 2018 return, you can purchase the software to do so here. 

If you need additional assistance, please click here to contact customer support.