What is a will in the context of estate planning?

A will is a legal document that provides explicit instructions for how a person's estate should be distributed upon their death. It allows the individual, known as the testator, to designate who will receive their assets, appoint guardians for any minor children, and express wishes regarding the administration of their estate. The creation of a will is a fundamental component of estate planning, as it ensures that the testator's intentions are honored and that their estate is administered according to their preferences.

The other options do not accurately reflect the purpose or nature of a will. A formal contract regarding the sale of property pertains to real estate transactions and does not address the distribution of an estate upon death. A document outlining the value of a property portfolio is more related to asset management rather than estate distribution. Lastly, a description of property taxes owed at death does not encompass the broader estate planning goals that a will achieves. Thus, the correct choice reflects the primary function of a will within the context of estate planning.