RCW 48.18.190 says each form that conflicts with, modifies, or extends a contract of insurance must be in writing and made a part of the policy. Insurers must file these forms under RCW 48.18.100 or 48.18.103. Insurers must file applications and policyholder notices if the:

(1) Application will be used under RCW 48.18.080; or

(2) Policyholder notice amends or modifies policy provisions.