A passport is a universally accepted international document that is sufficient for crossing the border and provides a person's identity and nationality. It is issued by the traveler's country of origin and provides proof of citizenship.
A visa is a document granting permission for entry into a country to fulfill a specific purpose. A visa is granted by the country the traveler is visiting and is typically stamped into the traveler's passport.
Visa and passport requirements are intended to strengthen border security while also allowing entry of citizens and legitimate foreign visitors in a more efficient manner. They also serve as identification for travelers when dealing with international customs agencies or embassies.
Some countries allow travelers to enter a country with only a passport, while others require both a passport and a visa. The requirements are largely based upon the diplomatic relations between the two countries, and also whether the traveler is in the country for business or pleasure.
Be prepared to submit proof of either a passport or visa to the customs officials when crossing international borders. It is best to research the requirements prior to departure to make sure you have adequately met all guidelines. Preparation will help to simplify and streamline your traveling.