A testator is a person who creates a legal document called a will, which outlines how their assets and property should be distributed after their death. The testator must be of sound mind and legal age to ensure that their wishes are valid and enforceable. In the will, the testator can name beneficiaries, who are the individuals or organizations that will receive their assets. Additionally, the testator may appoint an executor, a person responsible for carrying out the instructions in the will and managing the estate, ensuring that the wishes are honored according to the law.