According to the Teachings of Bahá'u'lláh, Prophet/Founder of the Bahá'í Faith, each individual has the obligation to write a will and a testament. Each is free to dispose of his/her estate in whatever manner he/she chooses. I always thought one's will and testament was a single document, but actually, each part deals with a separate aspect of life.
The will does just that: lays out the deceased's wishes for distribution of whatever material estate there is. "Bahá'u'lláh affirms that in drawing up his will "a person hath full jurisdiction over his property", since God has permitted the individual "to deal with that which He hath bestowed upon him in whatever manner he may desire..." - The Kitab-i-Aqdas, The Book of Laws p. 224
Provisions are set out in Bahá'í law, however, for how to deal with the material estate and inheritance thereof in the case of intestacy. These are not currently binding in places where civil laws take precedence, but they include portions for relatives, Bahá'í Institutions, and educators. This last one emphasizes the importance given to teaching by Bahá'u'lláh.
Division of the estate takes place after the Huqúqu'lláh (The Right of God) has been paid, any debts have been settled, the funeral and burial expenses taken care of. "If the property is not equal to the debts, the estate must be distributed in direct proportion to each debt. The settlement of debts is a most important command set forth in the Book." - Huqúqu'lláh compilation
Further, a will also provides for children and other dependents: "If the deceased should leave children who are under age, their share of the inheritance must be entrusted to a reliable individual, or to a company, that it may be invested on their behalf in trade and business until they come of age. The trustee should be assigned a due share of the profit that hath accrued to it from being thus employed." - The Kitab-i-Aqdas, p. 28
One thing a will does not do well is to insure that burial is according with Bahá'í law, because often the will is not read until after interment has already occurred and the heirs have been gathered. Therefore, Bahá'ís should make sure that their family or caregivers know what needs to be done. (See the article on Bahá'í Burial for details.)
A testament, on the other hand, is about one's spiritual estate. In it many people endeavor to pass on what they have learned and what they deem most important about their life journey. A testament can be a repository of family history, a personal sermon, a list of accomplishments and/or regrets. Or, in my case, a summary of what I have always wanted to tell my loved ones that they didn't want to hear at the time, LOL! Whatever the style or content, this instrument is just that: a personal testament, unique to each one of us.
Bahá'ís are instructed: "It is incumbent upon every one to write his testament. It behoveth him to adorn its heading with the most great name, to testify therein to the oneness of God as manifested in the day-spring of His revelation and to set forth such good deeds as he may wish to be realized, that these may stand as his testimony in the worlds of revelation and of creation and be as a treasure stored up with his Lord, the Protector, the Trusted one'." - Lights of Guidance, p. 192