Only three people in the world can travel abroad without a passport. Who are they?

There are only three people in the world who can travel abroad without a passport. Who are they?
To travel abroad, almost the entire population of the world needs a passport to prove their identity. However, there are three people who are exceptions to this rule: King Charles III of Great Britain, Emperor Naruhito of Japan, and his wife, Empress Masako.
The British monarch inherited the right to travel without a passport after the death of his mother, Queen Elizabeth II. The official website of the royal family also states that "the monarch does not need a British passport to travel abroad."
Instead of a regular passport, a special document is prepared in the name of Charles III. It requests that the holder be allowed to pass without let or hindrance, and be provided with necessary protection and assistance. Other members of the British royal family, however, use regular passports.
Emperor Naruhito of Japan and his wife, Empress Masako, also hold a special status. Furthermore, it is considered inappropriate for their status to undergo the same entry procedures as ordinary citizens when entering any country.
Therefore, instead of a passport, they are issued a relevant ministry document. However, the Ministry of Foreign Affairs of Japan must notify the destination country of their visit in advance. This exception does not apply to other members of the imperial family — they travel with diplomatic passports.
For information, members of the imperial family in Japan do not have surnames. Also, like the British monarch, the Emperor of Japan is a symbolic figure and does not participate in governing the country.

