<apex: facet> Component in Visualforce Page
The <apex: facet> is another important VF page component that acts as a placeholder for the content rendered in a specific part of the parent component. The header and footer of the <apex: dataTable> component are examples for which we can use the <apex: facet> component.
We use the <apex: facet> component for getting the user input for a controller property or method that doesn't correspond to a field on a Salesforce object.
The <apex: facet> component has only one attribute, which is given below:
The name is a string-type attribute that specifies the facet's name to be rendered.
Let's take an example to understand how we can use the <apex: facet> component on the VF page: