There are 3 main reasons you would need a travel document as a green card holder: Leaving the US for 6 Months or Longer/Frequent Travel. Leaving the US for a Year or Longer. Cannot Get a Passport from Country of Citizenship.
People Also Ask
Can I travel outside the U.S. with a green card? Yes, you can travel abroad as a green card holder — that's one of the many benefits of being a permanent resident. However, your trip must be temporary and you cannot remain outside the United States for more than 1 year.
A Green Card is valid for readmission to the United States after a trip abroad if you do not leave for longer than 1 year. If your trip will last longer than 1 year, a reentry permit is needed.
If you are a lawful permanent resident (green card holder), you may leave the United States multiple times and reenter, if you do not intend to stay outside the United States for 1 year or more.