According to Rules 2 and 3 of the official Academy Awards Rules, a film must open in the previous calendar year, from midnight at the start of January 1 to midnight at the end of December 31, in Los Angeles County, California, and play for seven consecutive days, to qualify, except for the Best International Feature Film, Best Documentary Feature, and awards in short film categories. The film must be shown at least three times on each day of its qualifying run, with at least one of the daily showings starting between 6 pm and 10 pm local time.
later
The Best International Feature Film award does not require a U.S. release. It requires the film to be submitted as its country’s official selection.
Actual rules are linked by the Wikipedia page a PDF.
From the Rules Section of the Academy Awards Wiki Page :
later
Actual rules are linked by the Wikipedia page a PDF.