Immediate actions: Actions that get executed immediately when a record is created or edited.Time-dependent actions: Actions that get executed after a certain duration of time, such as 10 days, before a record’s close date.
Workflow Action : A workflow action, such as an email alert, field update, outbound message, or task, fires when the conditions of a workflow rule are met. Email Alert : Email alerts are actions that send emails, using a specified email template, to specified recipients