Tex. Insurance Code § 1213.002

(a) The issuer of a health benefit plan by contract may require that a health care professional licensed or registered under the Occupations Code or a health care facility licensed under the Health and Safety Code electronically submit a health care claim or equivalent encounter information, a referral certification, or an authorization or eligibility transaction. The health benefit plan issuer shall comply with the standards for electronic transactions required by this section and established by the commissioner by rule.

(b) The issuer of a health benefit plan by contract shall establish a default method to submit claims in a nonelectronic format if there is a system failure or failures or a catastrophic event substantially interferes with the normal business operations of the physician, provider, or health benefit plan or its agents. The health benefit plan issuer shall comply with the standards for nonelectronic transactions established by the commissioner by rule.