A due to bank account is the accounting name for what correspondent banking calls a vostro account: an account that one bank maintains for another bank, so that it owes that bank the balance. The main entry explains how vostro accounts are used in cross-border payments.
In the account provider's balance sheet, these balances are liabilities, often reported as "due to banks" alongside customer deposits. They arise when a bank acts as a correspondent institution for respondent banks, holding their funds so that it can make and receive payments for them. The respondent records the same balance as an asset, "due from banks", which it calls its nostro account.
Because due to bank balances can be withdrawn quickly, regulators treat them carefully in liquidity rules, and banks monitor them as part of their funding. They are also subject to anti-money laundering controls, since payments passing through them often involve customers of the respondent bank. The difference between the terms is explained further in nostro vs vostro vs loro accounts.