My 6 year old son will be traveling to the US with my wife. I applied online, paid the fee and got the confirmation email. In that email, in the section about the required documents for all visas, it says:
Accompanying family members, unless entering the United States for another purpose, should present a marriage certificate (spouse) and/or birth certificate (for unmarried children under 21), as applicable.
What exactly does this mean? Should I also send his birth certificate by courier (he is eligible for courier application)?