You can apply materials to model elements in any of the following ways:
By category or subcategory
In a project, you can apply a material to a model element based on its category or subcategory.
For example, you can specify a material for the door category, and then specify a different material for a subcategory of the door, such as glass for a door panel.
In the Family Editor, when creating or modifying a component, you can use family type parameters to apply a different material to each piece of geometry in the component.
To apply materials to system families elements, see Applying a Material by Element Parameter.
By element parameter
In a project, you can select a model element in a view, and use element properties to apply a material.