Shards :
Shards are a premium currency purchased from the EA Origin Game store. They can be used to purchase javelin customization.

Additional Notes and Trivia

Before update 1.7.0, the text mentioned wrong information and mixed up shards with coin. Shards have always been premium and coin in-game currency since the game's launch.
This is the original text: Shards are a premium currency earned by completing challenges and weekly Path to Glory. They can be used to purchase javelin customization options or to extend Agent Bonuses.
Bioware has always made it clear that only cosmetics can be purchased using real world money. So, earning shards in game would have negated that statement, and the text was likely a remnant from early production. As for what Agent Bonuses are, we may never know.

• To see the main pages that aren’t a part of the Cortex but a part of the Lore, see below:
  • Legend of the Heart of Rage
  • Tutorials in Cortex
  • Rewards and Experience Bonus
• A list of all relevant cortex entries clustered in collections can be seen in Cortex Archives.