Tex. Estates Code § 751.0021

(a) An instrument is a durable power of attorney for purposes of this subtitle if the instrument:

(1) is a writing or other record that designates another person as agent and grants authority to that agent to act in the place of the principal, regardless of whether the term "power of attorney" is used;

(2) is signed by an adult principal or in the adult principal's conscious presence by another adult directed by the principal to sign the principal's name on the instrument;

(3) contains:

(A) the words:

(i) "This power of attorney is not affected by subsequent disability or incapacity of the principal"; or

(ii) "This power of attorney becomes effective on the disability or incapacity of the principal"; or

(B) words similar to those of Paragraph (A) that clearly indicate that the authority conferred on the agent shall be exercised notwithstanding the principal's subsequent disability or incapacity; and

(4) is acknowledged by the principal or another adult directed by the principal as authorized by Subdivision (2) before an officer authorized under the laws of this state or another state to:

(A) take acknowledgments to deeds of conveyance; and

(B) administer oaths.

(b) If the law of a jurisdiction other than this state determines the meaning and effect of a writing or other record that grants authority to an agent to act in the place of the principal, regardless of whether the term "power of attorney" is used, and that law provides that the authority conferred on the agent is exercisable notwithstanding the principal's subsequent disability or incapacity, the writing or other record is considered a durable power of attorney under this subtitle.