Need a copy of 1985 tax return, how do i get this?

A tax return from 1985 is not available.  The IRS only retains the last seven years of federal tax returns.

the best you can do is get copies of any w-2's for 1985 from the Social Security Adm for which there is a fee. Turbotax online does not retain those return either.  if you want copies for posterity, it's necessary to create a PDF and then save it to your computer and another copy somewhere else because computers do fail making your computer copy unretrievable.