Yes, you can execute a will (last will and testament) to that effect. You can choose between the two kinds of will, i.e., holographic will and notarial will.
A holographic will is entirely written, dated and signed by the hand of the testator himself. It is subject to no other form and may be made in or out of the Philippines. It need not be witnessed.
On the other hand, a notarial will must comply with the following requisites: (1) It must be in writing; (2) It must be in a language or dialect known to the testator; (3) It must be subscribed at the end thereof by the testator himself or by the testator’s name written by some other person in his presence and by his express direction; (4) It must be attested and subscribed by three or more credible witnesses in the presence of the testator and of one another; (5) Each and every page of the will must be signed on the left margin by the testator or by the person requested by him to write his name, and by the instrumental witnesses; (6) Each and every page of the will must be numbered correlatively in letters placed on the upper part of each page; (7) The will must contain an attestation clause stating: (a) the number of pages upon which the will is written; (b) the fact that the testator signed the will and every page or caused some other person to write his name, under his express direction, in the presence of the instrumental witnesses; (c) All the instrumental witnesses witnessed and signed the will and all its pages in the presence of the testator and of one another; and (
It must be acknowledged before a notary public by the testator and the witnesses.
Please do note that every will must be probated, meaning, a court case will be filed in order to give effect to the will. Probate is mandatory. The law provides that “no will shall pass either real or personal property unless it is proved and allowed in a proper court.” A will may be probated during the lifetime or upon the death of the testator. Probate of will during the lifetime of the testator is advisable if he wants assurance that his will will be probated as he himself can affirm the validity of the will.
Aside from the formalities of a will, you must also take into consideration the legitimes of your compulsory heirs. Legitime is that part of the testator's property which he cannot dispose of because the law has reserved it for certain heirs who are, therefore, called compulsory heirs. The legitime reserved for the compulsory heirs depends on who among the compulsory heirs will survive the death of the testator. The legitime will also differ depending on the number of compulsory heirs who survived the death of the testator.
For example: The testator left a will and was survived by one legitimate child and his spouse. In such case, the law provides that the legitime of the child consists of 1/2 of the estate of the testator. On the other hand, the legitime of the surviving spouse is equivalent to 1/4 of the estate of the testator. If the testator wants to leave 100% of his properties to his legitimate child, he cannot do so because the law says that the spouse is entitled to 1/4 of the estate. Thus, the testator can only give 3/4 of his properties to his legitimate child. If he gives more than that, the surviving spouse can file a case in court asking for the satisfaction of her legitime.
[Note that legitime differs from inheritance. In inheritance, there is no will or there is no valid will. Thus, the estate of the deceased passes to the heirs by operation of law. The inheritance of each heir (how much each will receive) is also provided for by law.]
Sorry for the long response. This subject is quite complicated. If you want to proceed with the will, it is always better to seek the services of a lawyer to avoid legal infirmities.