can I update my bank account info

If you have not filed your tax return you can change your bank information in the File section of the program when you have either a direct deposit of a tax refund or a direct debit of taxes owed.

If you have filed your tax return the bank information cannot be changed if you are receiving a tax refund.   

For federal taxes owed, see this IRS website if you need to change the bank information - https://www.irs.gov/payments/pay-taxes-by-electronic-funds-withdrawal

• Once your return is accepted, information pertaining to your payment, such as account information, payment date, or amount, cannot be changed. If changes are needed, the only option is to cancel the payment and choose another payment method.
• Call IRS e-file Payment Services 24/7 at 888-353-4537 to inquire about or cancel your payment, but please wait 7 to 10 days after your return was accepted before calling.
• Cancellation requests must be received no later than 11:59 p.m. ET two business days prior to the scheduled payment date.

HOW TO CHANGE OR ENTER BANKING INFORMATION FOR REFUND

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-refund/change-transferred-direct-deposit-information/L77NCbU6D_US_en_US?uid=m6tuh572

You cannot  change banking information while your return is in pending, nor can you change it after the return is accepted.  The IRS does not allow it.

Did you already e-file?  If you did NOT e-file you can go to the FILE section  step 2 to enter/change how you want to receive your refund.  If you want direct deposit you need the routing number and your own account number. 

If you e-filed:

Banking information for direct deposit is wrong or closed

If you entered incorrect banking information for your refund, you can change it if your return is rejected.  If it is accepted, however, it is too late to change it.  The bank will reject the refund and send it back to the IRS.