To split your refund in TurboTax Online, you'll need to choose the credit card payment option (assuming you're not filing for free).

 

If you chose the Pay With My Refund option, follow these directions to change your payment method, then come back here.

 

1. When you get to the How would you like to receive your federal refund? screen, select the last option: Split my refund between multiple bank accounts or U.S. savings bonds. Then select Continue
2. On the next screen, select I want to deposit my federal refund into multiple bank accounts and select Continue
3. Enter the amount you want to go to the first account and then enter the account information. When finished, select Add another bank account
4. You can split your refund among as many as three accounts. When you're finished entering your account information, select Continue
5. Review your bank information and deposit amounts, and select Continue if all looks well. If you need to make changes, select Edit next to the entry you need to modify

You can also use this method to put some of your refund in U.S. Series I savings bonds.

https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-refund/split-refund-2-different-accounts/L71Rf5NI0_US_en_US