I accidentally put the wrong bank account number on my taxes for my refund. How can I fix it after I filed my return?

If your tax return has been filed and accepted, there is no way to fix it. If the IRS is unable to direct deposit your refund, they will issue a paper check and mail it to the address on your tax return. 

How long does the paper check take after this situation?

I did the same thing how long does it take to get a check in this situation

Same thing happened to me long does it take to get a check

Same here called the bank, and the irs (THE IRS BLOWS) and i still couldnt get an answer

If you accidentally enter someone else's account number or wrong account number it says chances are whatever Bank it comes to will decline the deposit because the refund name does not match the account holder name

I Googled it I researched if I could put my refund in someone else's account