Regarding the Declaration of Intent (DOI), Washington State homeschool law states:

RCW  28A.200.010
Home-based instruction—Duties of parents—Exemptions from state learning goals, state learning standards, and high school assessments

(1) Each parent whose child is receiving home-based instruction under RCW 28A.225.010(4) shall have the duty to:

(a) File annually a signed declaration of intent that he or she is planning to cause his or her child to receive home-based instruction. The statement shall include the name and age of the child, shall specify whether a certificated person will be supervising the instruction, and shall be written in a format prescribed by the superintendent of public instruction. Each parent shall file the statement by September 15th of the school year or within two weeks of the beginning of any public school quarter, trimester, or semester with the superintendent of the public school district within which the parent resides or the district that accepts the transfer, and the student shall be deemed a transfer student of the nonresident district. Parents may apply for transfer under RCW 28A.225.220;