The IRS is using the deposit information from the 2019 return in most cases.  Unless you manually updated the account information at the IRS Get My Payment  site your payment may go to that site.  Make sure you check the status of your payment before you file and remember that stimulus payments will continue to be processed until February 5. 

If you do not receive a payment and file to have it added to your refund, then you will put the correct account information into your tax return and that account will be used to deposit your refund and future payments.

I should be more clear. Both stimulus payments deposited in my ex-wife's account from the info they had for 2019. 

Also: The IRS "get my payment" site does not allow updating your information anymore.

I already filed my taxes this year (2020) but since I don't get a refund they never asked for my direct deposit account. Is there any other way to update/add my information for the future?  

The IRS in the future may open the "Get my payment" site for updates.  However, if that does not happen, the IRS has published that those individuals with no bank account information on file will receive payments by an Economic Impact Payment card (debit card).  

See the question "Will my payment be issued on a debit card?" in this link.