You can add your direct deposit information when you file your 2020 tax return. Your bank information is not stored in your TurboTax account preferences, it can only be found on your tax return if you choose to have your refund direct deposited. Stimulus checks were sent out using the information from either your 2018 or 2019 tax returns. Your banking information would have to have been on those returns or you would have had to enter your bank information on the IRS's non-filers portal last year.
When you get to the filing screen in TurboTax, choose direct deposit and enter your banking information there. Any tax refund (including missing stimulus payments) will be direct deposited to that account once the IRS processes your return.
Please let me Change my preferences for my refund from mailing to direct deposit Please
This article will help you change or review your refund method.