In the United States, potential jury members are notified of their duty by a summons. a phone call. an e-mail. a text message.

Your answer is by a summons

A Jury is formed by people selected for a Jury trial. They are chosen among the community, after their names are include in a list and compiled from any of the documents (Identification card, driver's license, voter registration). This process is done using a random method. When the list is complete, a summons (official demand) is sent by mail to notify the people who were selected.