If you are looking for the option to have your refund go into 2 bank accounts, the only way to split it is to select to purchase a savings bond. Then on the next screen, you will see option to split your refund into multiple bank accounts. See workaround below if you do not want to keep savings bond.
WORK-AROUND: Choose savings bond and add at least $50 for one. Then continue through and add your bank accounts and once you have added them, delete the savings bond from the page that shows list of how you divided up the refund. This will prompt you saying you have a balance left. Edit one of the bank accounts to add the rest of that amount to it.
How do I split my refund into 2 different accounts?