Is trust fund like any other bank saving accounts where funds can be accessed easily (eg. ibanking transfer, ATM card) by the trustee? Other than trustee, who else have the rights to access the funds?

Any parent here included testamentary trust in your will? What are your considerations and typical instructions like? Should we liquidate all assets to put inside the trust, or let the trust hold the different forms of assets till the children grow up to decide for themselves, with the assumption that both parents are no longer around. Thanks in advance!