California's Requirements to Create a Valid Will

1. **Age and Capacity**: The testator (person making the will) must be at least 18 years old and of sound mind. This means the testator understands the nature of the will, knows the extent of their property, and knows the natural objects of their bounty (e.g., close family members).

2. **Writing**: The will must be in writing. This can be typed or handwritten.

3. **Witnesses**: A typical attested will must be signed by at least two competent witnesses. These witnesses must see the testator sign the will or acknowledge the signature, and then they must sign the will themselves in the presence of the testator.

4. **Signature**: The testator must sign the will. If the testator cannot sign, someone else can sign on the testator's behalf, but this must be done in the testator's presence and at their direction.

5. **Holographic Wills**: California recognizes holographic wills, which are wills that are written, dated, and signed entirely in the testator's handwriting. These wills do not need to be witnessed. However, it's essential that the material provisions and the testator's signature are in the testator's handwriting. If any part of the holographic will is unclear, extrinsic evidence can be introduced to clarify the testator's intentions.

6. **Revoking or Changing the Will**: A will can be revoked by the testator at any time before their death, as long as they are of sound mind. This can be done by creating a new will, creating a codicil (an amendment to the will), or by physically destroying the will (e.g., burning, tearing, or otherwise mutilating it with the intent to revoke).

7. **Self-Proving Affidavit**: California does not use self-proving affidavits in the same way some other states do. However, California does have a "statutory will" form that includes an attestation clause, which serves a similar purpose in that it can help confirm the will was properly executed.

8. **Property Disposition**: While not a requirement for a valid will, it's essential to be clear about how you want your property distributed. If certain provisions of the will are found to be invalid, those portions of the estate may be distributed according to California's intestacy laws.

9. **Digital Assets**: It's a good idea to consider digital assets when creating a will. While specific provisions might not be outlined in the basic requirements for a will, addressing digital assets and providing clear instructions on how they should be handled can be crucial.

10. **Special Provisions for Non-Residents**: Non-residents can create a valid will in California if the will is executed in compliance with California's laws, the laws of the place where the will was executed, or the laws of the place where the testator was domiciled when the will was executed or at the time of death.

It's crucial to consult with an attorney familiar with California's estate planning laws when creating a will. This ensures that your wishes are accurately and legally documented and that your assets are distributed according to your intentions. Laws and regulations can change, so always check for the most up-to-date information or consult with a legal professional.