The power of testation is the ability to make a legally valid will, determining how one's property, assets and affairs will be handled after their death. Synonyms for this term include testamentary power, testamentary capacity, testamentary competence, and testamentary authority. These phrases all refer to the same concept, and describe the legal and mental requirements necessary to create a valid will. The power of testation is a fundamental aspect of estate planning and can be utilized to ensure one's wishes are carried out after their passing. Regardless of the term used, it is crucial to understand the importance of having an executed will to protect one's legacy and loved ones.