A workflow rule is an automation that triggers when certain criteria are met to set an action into motion.
It is defined in 3 stages.
First the Evaluation Criteria (user action): evaluate the rule criteria each time a record is created, or created and every time it’s edited (any field of the record is updated) or created and every time it’s edited to subsequently meet criteria (filter on certain fields only).
Second the Rule Criteria: set the conditions (or Rule Criteria) that would trigger the actions.
And finally, create the actions that will be automated: Task, Email, Field Update, and Outbound Messages.
It is also possible to add a Time Trigger which will store the action in a queue and when the date is reached, the time-dependent action is executed. The action is effectively created when the trigger criteria are met, but its execution is deferred. The pending action can be viewed and/or canceled in the Setup / Monitor / Workflow queue.
Workflow rules are limited to 500 per object. You can follow the limits per object in Customize / Object Name / Limits. Workflow rules can trigger other workflow rules.
Example: A user updates the opportunity status to ” proposal received “, a notification email will be sent to the record’s owner.