Final answer:
Federal papers can be served by anyone who is 18 years or older and not involved in the case at issue, in accordance with the 26th Amendment of the U.S. Constitution.
Step-by-step explanation:
Federal papers may be served by anyone 18 years or older and not a party to the case at issue. This is because the right of citizens who are 18 years of age or older to participate in legal actions, including voting and serving legal papers, is protected under federal law. Specifically, the 26th Amendment of the United States Constitution, which lowered the voting age from 21 to 18, can be applied by extension to serving legal documents, as it speaks to the legal responsibilities and privileges of citizens who have reached the age of 18.