Scroll of Wisdom identifies an unidentified item. Right-click this item then left-click an unidentified item to apply it.
It is always suggested to identify an item before selling or using it. In the following example, an unidentified Champion Kite Shield can be sold for five Transmutation Shards, while an identified item can be sold for ten Alteration Shards.
It is also a good habit for players to keep a stack of Scrolls of Wisdom in their inventory in order to identify items or strongboxes without needing to return to town first.