how to clear cache on macbook air

• "Safe Mode" deletes certain cache files maintained by macOS: How to use safe mode on your Mac - Apple Support
• If you are asking about deleting Safari cache files: Clear your browsing history in Safari on Mac - Apple Support
• If you are asking about deleting Safari's cookies and website data: Manage cookies and website data in Safari on Mac - Apple Support

Bear in mind the purpose of cache files is to maximize a system's efficiency.

Shut it down.

If you are referring to the Safari browser: Clear your browsing history in Safari on Mac - Apple Support