Your question is probably intended as a joke. In the event that aliens from space ever make contact openly with the planet Earth or any nation thereof, they would have to establish some kind of diplomatic agreement with some national government before there could be such a thing as legal Immigration from wherever it is that they come from.
Joke answer:
They likely won't need a green card if they are already Green.
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Why they call it a Green Card.The first Resident Alien Card (Green Card) had green-stripes on one side and was issued many years ago (1950s). There have been several revisions to the Resident Alien Card with the newest being mostly white in color. The Resident Alien Card version that is carried by most Lawful Permenant Residents is the pink/salmon colored card (second newest card). T
Then I would get my Green Card
The alien registration number starts with the A.
you just ask the green card holder if you can borrow his.
An immigrant who is unlawfully within the US is not eligible for permanent residence status (green card).
Get on a very long waiting list to get your green card. You wouldn't be an alien if you were legal
an alein cant get a green card they are already green silly!!!
haha lol why not?
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Then the alien loses the green card- if still outside the U.S.
Alien Registration Number is only for Green Card holders.