Do you mean the bank account information that you entered for direct deposit of your refund? It's on lines 20b, 20c, and 20d of your 2018 Form 1040.
If you need a copy of your 2018 tax return, and you filed it with TurboTax Online, see the following FAQ for instructions.
How do I get a copy of the 2018 return I filed in TurboTax Online?
