Final answer:
A person can sign a life insurance application at the age of 18 years, as individuals younger than this are generally considered minors and cannot legally enter into contracts.
Step-by-step explanation:
The minimum age at which a person can sign a life insurance application is 18 years. This is due to the legal principle that individuals under the age of 18 are typically considered minors and are not legally able to enter into contracts, including life insurance policies, independently.
Once a person reaches the age of majority, which is generally 18 years in many jurisdictions, they can enter into legal contracts and therefore sign for life insurance on their own behalf.