What is written on the back of American passport?

The Secretary of State of the United States of America hereby requests all relevant personnel to allow the American citizens/nationals mentioned here to pass through without delay or hindrance, and to give all legal assistance and protection when necessary.

The Secretary of State of the United States of America hereby requests relevant persons to facilitate the passage of this American citizen/national and provide legal assistance and protection when necessary.

Extended data

Cover content of China passport

The three versions of China passport, whether it's version 1987, version 1992 or version 1997, are "the people of China and the Ministry of Foreign Affairs of China require the military and political organs of various countries to provide convenience and necessary assistance to passport holders", instead of "please strictly abide by local laws and respect local customs".