I need to obtain a signed copy of my return for an income reduction form. How to I obtain that through the free version of Turbo Tax?

Download  your return and print it.  Then you have to sign it in ink  on the bottom of the  2nd page.

How to get or print a copy after filing
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-get-a-copy-of-a-return-i-filed-this-year-in-turbotax-online/01/25932