Difference between audit, attestation, and assurance services

What is the difference between audit, attestation, and assurance services? And how do the answers provide value to stakeholders? How can auditors effectively plan an audit in a dynamic and uncertain environment? Provide an example to describe your answer. In your opinion, what are the benefits of assessing the effectiveness of internal controls over financial statements ICFR to the audit process, other than being a requirement of PCAOB?