Whether or not you can switch from receiving a paper check to getting your refund direct deposited, or vice-versa depends on if your tax return has already been filed and accepted or filed and rejected.
If you have already filed and submitted your tax return you are unable to edit the bank account information, as well as the direct deposit option, once the return has been accepted. If your return has been filed and submitted and rejected then you are able to change the information.
If the IRS is unable to deposit your refund into your account, they will mail you a refund check. If the info you entered is someone else's account, don't worry – some banks won't deposit tax refunds into accounts where names don't match up.
Hope this was helpful!
Can you please change my return from paper check to direct deposit