How can I change my bank account number and routing number to receive my tax return

I need to change my bank account number before I file my return

If your return has been accepted (or mailed), there is no way to change your account for direct deposit.

If the info you provided is for a closed or invalid account, the IRS will mail you your refund check. If the info you entered is someone else's account, some banks won't deposit tax refunds into accounts when the names don't match.  The best (and only) way for you to track your federal refund is to call the IRS 1-800-829-1040.

If your recently-filed return is in pending status, wait until it's either accepted or rejected.

If your return was rejected, go through the File section again to update your bank account before re-submitting your return. Don't forget to also address whatever problem caused the rejection.

I'd like to change my bank account now please or tomorrow 

Could you help to change my bank account please?

You can only change it when you file your 2020 return.  Which won't be able to file until Jan 27.  When you finish your return you enter or change it under the File tab.