What action is used to create an asset hierarchy in the Asset application?

Creating an asset hierarchy in the Asset application involves defining the relationships between various assets, which is accomplished through the application of an item assembly structure. This structure allows you to organize assets into a hierarchy, enabling better management and understanding of how different assets are related to one another within the system.

When you apply an item assembly structure, you can represent parent-child relationships between assets, which is essential for maintenance planning, tracking dependencies, and understanding how failures in one asset can impact others. This structured approach helps in analyzing asset performance and ensuring more effective maintenance strategies.

The other options do not contribute directly to the formation of an asset hierarchy. While creating condition codes, adding inventory items, and defining tool usage are useful functions within the Maximo system, they do not facilitate the organization of assets into a hierarchical structure. Therefore, applying the item assembly structure is the correct action to create an asset hierarchy.