In a UML model, you can add class diagrams to provide various static structural perspectives of the system that you are modeling.
The complexity of your model determines whether you need one or more class diagrams to show the structure of a system.
You can add a class diagram directly to a model or to a model element, such as a package. For example, you can add a class diagram to a package to help describe the structure of your system. You might want to organize related classes under a particular package, or show your design and implementation classes as children of your analysis classes, which describe the system at a higher level.
To add a class diagram to a model element:
Parent topic: Creating and modifying class diagrams
Parent topic: Modeling static structure by using class diagrams
Related concepts
Class diagrams