Last will must be notarized

Every will must be acknowledged before a notary public by the testator and the witnesses. The notary public shall not be required to retain a copy of the will, or file another with the office of the Clerk of Court. (Article 806 of the New Civil Code)

A notary public (or notary or public notary) is a public officer constituted by law to serve the public in non-contentious matters usually concerned with estates, deeds, powers-of-attorney, and foreign and international business. https://en.wikipedia.org/wiki/Notary_public

The notary public cannot be considered a third witness. He cannot acknowledge before himself his having signed the will. To allow such would have the effect of having only two attesting witnesses to the will. (G.R. No. L-32213. November 26, 1973) Nevertheless, if there are already three credible witnesses and the notary public signs as a witness, this does not affect the extrinsic validity of the will.

Whether or not the notary signed the certification of acknowledgment in the presence of the testatrix and the witnesses does not affect the validity of the codicil. Unlike the Code of 1889, the New Civil Code does not require that the signing of the testator, witnesses and notary should be accomplished in one single act.

A comparison of Articles 805 and 806 of the New Civil Code reveals that while testator and witnesses must sign in the presence of each other, all that is thereafter required is that "every will must be acknowledged before a notary public by the testator and the witnesses" (Art. 806). This means that the latter should avow to the certifying officer the authenticity of their signatures and the voluntariness of their actions in executing the testamentary disposition. Article 806 of the New Civil Code does not contain words requiring that the testator and the witnesses should acknowledge the testament on the same day or occasion that it was executed. (G.R. No. L-7179. June 30, 1955)