Events are used to pause and resume actions in the process flow. It also helps you to notify the user of actions performed in the business process. There are two types of events involved in building a process flow:

Call a Subflow – This event allows you to invoke an independent process app.
Notify – This event helps you notify users through the channels.
Delay – This event helps you in delaying the execution of a step in the process app by using a condition.