Proper documentation and identification is required for entry into foreign countries and for re-entry into the United States. Requirements vary by country based on citizenship, purpose of visit and length of stay. The U. S. State Department provides information regarding the travel documents required for the country in which you will be traveling at www.travel.state.gov.
Along with the originals, take a copy of all your travel documents (including passport, birth certificate, visa, work permit, confirmation of vaccinations and confirmation of health insurance) with you and leave copies with someone at home.
U.S. Passport: https://travel.state.gov/content/passports/en/passports.html
Visa Service Companies:
Travel Document Systems (traveldocs.com)Travel Visa Services (passportsandvisas.com)