TT doesn't have your 2018 return because it was done thru H&R. It is unclear if your niece prepared your return using their software in which case she was probably legally required to furnish you with a copy. on the other hand, if you used their self-preparation software like TT, you'll need to access that a/c to retrieve it. at worst you can request a transcript from the IRS. it will not have state data.
https://www.irs.gov/individuals/get-transcript
