31 CFR §363.33

1. (a)An attorney-in-fact who provides a copy of a durable power of attorney granting him or her the authority to conduct TreasuryDirect transactions on behalf of the owner may conduct transactions online.
2. (b)An attorney-in-fact who provides a copy of a limited power of attorney may only conduct transactions that he or she is permitted by his or her power. Such transactions will be through an offline process.
3. (c)A written copy of the power of attorney must be sent to the address provided in § 363.5. We may require any additional evidence that we consider necessary to support the power.