What must you do to create an Apex task?

To create an Apex task, writing a script is essential because it involves programming in Apex, which is Salesforce's proprietary language used for developing applications on its platform. By writing an Apex script, a developer can define specific logic and operations that the task should perform. This process may include creating instances of Apex classes or executing specific methods, such as interacting with Salesforce records or running business logic.

The other options do not pertain to how tasks are created within Apex. Calling a function could be part of the Apex script but does not encompass the entire task creation process. Filling out a form describes a user interface interaction rather than coding. Scheduling a meeting pertains to calendar functionality, which is unrelated to Apex development. Overall, writing a script encompasses the entire development process that leads to the creation and execution of Apex tasks.