IRS 2014-7 filing amended returns for last 6 years?

I have been the Personal Care Attendant for my partner since 2019. She lives in my home and is disabled receiving SSDI. She qualifies for CADI waivere under Medicaid in Minnesota. I was not aware that this income could be tax exempt until just now. Can I file these amended returns in Turbo Tax? How far back can I go? What documentation is needed?