Wi-Fi Calling lets you talk and text from indoor locations where itâs hard even for a strong cellular signal to reach. Wi-Fi Calling can be used in the Domestic Coverage Area (U.S., Puerto Rico, and U.S. Virgin Islands) and from most international countries.
The U.S. Passport Card. This... is the U.S. Passport Card! This card can be used as an official I.D. in many countries abroad. However, it cannot be used for international travel by air. If you are going to travel to an international destination, you will still need to take your passport book with you.
The U.S. Passport Card can be used to enter the United States from Canada, Mexico, the Caribbean, and Bermuda at land border crossings or sea ports-of-entry and is more convenient and less expensive than a passport book. The passport card cannot be used for international travel by air. I think its better to just get a passport. They are good for 10 years so its minimal investment. Also good advice, don't ever lose your passport overseas, keep it safe as its a pain in the ass and possibly a long process to get another one.