。
She deposited the money in the bank.
Literal
She [topic-は] that money [object-を] bank [in-に] entrusted.
預ける is the more general 'entrust / leave with' — you can 預ける anything from a coat at the cloakroom to a child at daycare to your savings at a bank. The に here marks the recipient of the entrustment: where (or to whom) the thing is being left. Banking-specific verbs like 預金する exist, but the everyday 預ける covers it perfectly well. The reverse direction — withdrawing — is お金を下ろす, taking money 'down' from the account.