Broadly speaking, trust accounts and in-trust accounts allow you to deposit, manage and withdraw the money on behalf, and to the benefit, of a third party.  

Trust accounts are frequently operated by liberal professionals, such as lawyers and notaries, who use them to handle their clients’ funds.

For example, a notary would deposit the sum of a property sale into their trust account and then send the money to the seller once the required verifications have been completed.

Lawyers use trust accounts to deposit retainer fees and disbursements from their clients. Afterwards, they can transfer these sums to their administrative account once their work has been completed.