Book Eight Chapter Three (Testamentary Succession) of the 2007 Civil Code addresses the making of a Will.
Under the 2007 Civil Code, persons who have attained the age of majority (18 years old) and minors who have been released from guardianship or parental power may make a Will. The testator must have the capacity to make a Will at the time of making the Will. Generally, a Will is drafted by a lawyer familiar with the laws of the jurisdiction where the succession property exists. The succession is “opened” at the residence of the deceased upon his or her death.
Wills must be made in accordance with the forms prescribed in the 2007 Civil Code, otherwise they shall be null and void. Such forms can be a notarised document, privately produced document or secret document. There is no particular form to follow for making a Will, so long as the Will can be acknowledged as a Will.

Article 1173 – Will by Notarial DocumentA will by notarial document must comply with the following formalities:

• Two or more witnesses must be present;
• The testator must orally declare the tenor of the will to the notary;
• The notary writes down the contents of the testator’s will and reads it aloud to the testator and the witnesses;
• That, after acknowledging the contents of the writing correct, the testator and the witnesses each note their name, age, address and affix signature on it; provided that if the testator is unable to write or sign, the notary shall note the above matters and sign in lieu of the testator and make an additional note of the reasons for so doing;
• that the notary dates and signs the document.

Article 1174 – Will by Privately-produced document

The testator must hand-write the whole text of the will and date and and sign it. A privately produced will written by another person (other than the testator) or using a typewriter is null and void. Any additions or other alteration of a privately produced will shall be null and void unless the testator indicates the place thereof, makes an additional entry that an alteration has been made, and specifically signs such entry.
There are some requirements/allowances for special circumstances such as where the testator is under guardianship (persons under legal protection); in imminent danger of death; being held in quarantine; mute or deaf.

Signature (or thumbprint) is important for every case. A date is not absolutely mandatory but an undated Will is valid if, and only if, such Will does not conflict with another Will made by the same testator. Undated Wills that contradict each other shall each be rendered null and void to the extent of the contradiction.

Witnesses:

Witnesses are necessary to make a Will valid and incontestable.
A successor who is not of Cambodian nationality, cannot hold real proprietorship of Cambodian land. Where a successor of land is a non-Cambodia, if none of the co-successors with prior ranks in the succession hold Cambodian nationality, the successors shall constitute a juridical person, and all of those co-successors with prior ranks shall jointly carry out the management and disposition thereof. If all of the co-successors with prior ranks in the succession effected absolute or qualified acceptance and, within three months after such acceptance, have sold the land as the person with the authority to dispose the succession property, the sales proceeds thereof shall form the succession property, and the succession juridical person shall then be dissolved. If all of the co-successors with prior ranks in the succession do not jointly sell the land within three months after they affected the absolute or qualified acceptance, the ownership of the land shall be succeeded to by successors with next rank in the succession who hold Cambodian nationality. In such a case, the succession juridical person shall be deemed as not having existed.

Cambodian citizens living outside Cambodia
Cambodian citizens living abroad can make a Will before a Cambodian consul who performs as a notary (for notarial document or secret document which is to be kept by a notary).

Successors of Mixed Cambodian-Foreign Parentage

An instruction for the Supreme Court (not sure about the date) provides that this equality principle should be scrupulously followed and there’s no distinction between children whether they are full-blooded or half-blooded with respect to succession.