There are three types of reports produced:
Notice To Reader – does not provide any level of assurance to the user of the statements
Review Engagement – provides a limited level of assurances to the user of the statements
Audit engagement – provides the highest level of assurance of the user of the statements
Usually, the use of assurance engagements are a result of bank financing requests, owners who may not be actively involved in the business or for businesses who might potentially be looking to be sold in the near future.