A will is legally valid even if it's not registered or notarised, as long as it meets specific criteria. Key requirements include being in writing, signed by the testator, and attested by two witnesses who know the testator. The will must clearly identify the testator, the beneficiary, the property being transferred, and any conditions. It should also confirm the testator's free will and mental capacity, and include the date of signing and details of the witnesses. A will can be written on plain paper and does not require stamp duty.