A passport is a must when you plan to travel out of your country of residence. It is an identity card that endorses your legitimate citizenship. Without a valid passport, you will not be allowed to enter any country.
A passport is a document, issued by a national government, which certifies, for the purpose of international travel, the identity and nationality of its holder. The elements of identity are name, date of birth, sex, and place of birth.
A passport does not of itself entitle the passport holder entry into another country, nor to consular protection while abroad or any other privileges. It does, however, normally entitle the passport holder to return to the country that issued the passport.