The datacard was used to transfer and store large amounts of information. A group of datacards was referred to as a datapack. Alternative data storage and retrieval devices were known as datadiscs or data plaques. Two large datadisc manufacturers were Corellia Digital and the Bay-Suwe Combine.
During the Clone Wars, a group of clones were sent to Christophsis to retrieve a number of datapacks, containing vital information, before the Separatist forces, which had overrun the planet, could get their hands on them.
R2-D2 carried a datacard containing the plans to the first Death Star that was given to him by Princess Leia during the Battle of Tatooine during the Galactic Civil War, shortly before her capture by Darth Vader and the 501st Legion.
During the Galactic Civil War, various spacers who sought out treasure also found some datadisks that contained maps to various treasures, of which at least 9 existed.
Behind the scenes
Datacards store and transfer data to and from datapads in the same way floppy disks and USB flash drives are used with computers. They can be used in the way a PDA reads secure digital (SD) cards. This was shown on-screen with fictional technology decades before the real world devices.