Your banking information will not go to the IRS until you file your 2020 return. Just entering it on the site will not send it to the IRS.
If you did NOT e-file you can go to the FILE section and change how you want to receive your refund. If you want direct deposit you need the routing number and your own account number.
You cannot change banking information while your return is in pending, nor can you change it after the return is accepted.