Turbotax could e-file amended returns when the IRS had the e-filing system open. Since they closed it on October 20, nothing can be e-filed including amended returns. What we don't know (because e-filing amended returns is new this year) is if you will be able to e-file an amended 2019 return when the 2020 e-filing season opens on January 27, 2021. For now, you can file by mail or wait and see if e-filing will be allowed in January.
