A notary public is involved in the creation of public notarial wills and secret notarial wills.
Literal
Public-notarial-deed will [attributive-の] creation [or-や] secret-notarial will [to-には] notary-public [subject-が] involves-[polite-ます].
Legal/notarial terminology. 公正証書遺言 ('public notarial will') and 秘密証書遺言 ('secret notarial will') are two of the three types of Japanese wills, created with notary involvement. 公証人 ('notary public') is the legal officer. 関与する ('to be involved in, to participate in') is formal. A typical sentence from legal/estate planning guidance.