If you used TurboTax to complete and file the original tax returns then see this TurboTax support FAQ for amending the returns - https://ttlc.intuit.com/community/amending/help/how-to-amend-change-or-correct-a-return-you-already-filed/01/25588
i want to amend my 2018 taxes
Look at the prior message. It has the TurboTax support link for amending a tax return...