Passports need to be shown before entering a foreign country. Whether you drive, take a bus, fly, or arrive by boat, the officials from your destination country will be waiting for you, and they will not let you into the country until they see your passport.
Customs and Declarations
At customs, you will be asked a few questions about how long you plan to stay, what you plan to do on your trip, and if you need to declare anything. Declaration requirements vary from country to country, but some of the items that need to be declared include everything from jewels and medications to dirt on the soles of your shoes.
If the customs official is happy with your answers, he or she will stamp your passport. The stamps tells which port of entry you were at as well as how long you are allowed to be in the country. It may have additional restrictions outlined on it. For instance, the entry stamp may say that you are not allowed to work.
Certain countries require travelers to have visas in order to gain entry. In some cases, you can get the visa at the port of entry, but in most cases, you need to get the visa before entering the country. To get a visa, you need to download a visa application from the website of the country you are planning to visit.
Then, you need to send the completed application with your passport to the embassy or consulate of the destination country. If they approve your visa request, they will stamp your passport with the relevant visa information and send it back to you.
As you travel between countries, you may notice that your passport is not checked at every border. For example, if you are traveling in the Europe Union, you typically do not need to present your passport each time that you get into a new country.
Connecting with Home
If you have trouble while abroad, you can use your passport to get into the US embassy in whichever country you are in. Remember, you also have to present your passport when you get back home.