An ordinary passport, the most common kind, enables you to travel internationally as a citizen of your country. This document typically entitles you, the bearer, to return to the country issuing the passport at the conclusion of your trip. Passports are required for all international travel. Without this document, you will not be allowed to board international planes or enter another country, even if travel there doesn't require a visa.
Government employees on official business might obtain an official passport, and diplomats have the right to a special diplomatic passport. These last two passports merely reflect the nature of the owner's particular line of work while abroad; special rights might apply, such as diplomatic immunity.
Emergency passports can be issued to the owner of a passport by their embassy when they have lost the original passport while abroad.
U.S. passcards, or passport cards, have the same basic function as passports, but they can be used only for surface travel by U.S. citizens between the U.S. and Canada, the Caribbean, Bermuda and Mexico. Instead of a small booklet, like a regular passport, they come in a convenient card form, much like a regular ID card. They have been issued by the U.S. since 2008 and are cheaper than a regular passport book. They are not valid for international air travel or travel outside their geographical restrictions.
Countries issue visas to allow foreign visitors to travel within their borders. Visas typically set conditions regarding the length and purpose of a stay and even the areas permitted for travel. Usually stamped into a visitor's passport, visas specify arrival and departure dates. Many tourist visas can be issued at the airport upon arrival in the country, though some countries require foreigners to obtain visas from the consulate or embassy well before their departure date, particularly in the case of immigrant visas. Costs vary by destination.
Some countries waive visa requirements for Americans because of reciprocal agreements. If one exists with the country you're visiting, the immigration officials will simply stamp your passport upon arrival, at no cost.
To apply for your first U.S. passport, you must appear in person at one of the many passport facilities throughout the country (see References). This procedure requires you to fill out form DS-11, and present it together with evidence of U.S. citizenship (birth certificate, residence permit, etc.), identification (ID card, driver's license, etc.), the corresponding fee and a passport photo.
When your passport expires, you can apply for a new one by mail if you have the old one at hand, by filling out form DS-82 and mailing it together with your old passport to the passport agency. If you are applying for a new passport because your old one was damaged -- although you may still have it hand -- you will have to apply for a new one in person. If it was lost or stolen, you'll fill out an additional form (DS-64) and present it together with the DS-11 form, evidence of U.S. citizenship, identification, corresponding fee and passport photo, at your local passport agency.
The procedures to obtain a visa vary based on the law of the country you intend to visit and the length and purpose of your stay. But the requirements to obtain one are pretty standard: you will need a valid passport, completed paperwork and the ability to pay the fee, in addition to documentation justifying your travel to the country (the exact type of documentation varies by destination). You will also usually need a passport photo.
