The items for summoning and dispelling anomalies are located in the Mysticism section of the Store and Inventory.
An item used for summoning anomalies is activated from the Inventory by pressing the Use button, and the summoned anomaly appears in a random location.
Items used to dispel anomalies are activated in the location or mini-game entrance window.
You can also get them as a reward for assembling collections and completing game events.