Final Answer:
In Salesforce, there are two primary ways to invoke an Apex class: through triggers and through anonymous code execution.
Step-by-step explanation:
Salesforce provides developers with two main methods to invoke an Apex class. The first method is through triggers, which are pieces of code that execute before or after specific events occur, such as record insertion, update, or deletion. Triggers are associated with objects in Salesforce, and they can call methods from Apex classes to perform custom logic.
The second method is through anonymous code execution, where developers can execute Apex code directly in the Developer Console or via the Salesforce Command-Line Interface (CLI). This allows for quick testing and execution of Apex classes without the need for creating triggers or other components.
Two ways to invoke an Apex class exist in Salesforce.