<apex: define> Component in Visualforce Page
It is one of the most used components on the Visualforce page responsible for providing content for the <apex: insert> component, i.e., defined in the VF page.
We use this method to get input from the user for the controller method that doesn't correspond to a field on a sObject field.
The <apex: define> component has only a single attribute, i.e., name.
The name is a string-type attribute used for specifying the name of the insert component into which the content of this defined component should be read.
Let's take an example to understand how we can use the <apex: define> component on the Visualforce page.