Hi @DineshPrasanth , great question!
High level:
Occurrences are the "number of hits where a given dimension was set or persisted".
Page Views are a subset of hits where the page view tracking call is sent.
Visits are a count of sessions that combine hits into a container. Typically, a new session begins after 30 minutes of inactivity, though this can be customized.
Visitors is typically based on marketingCloudID, so each unique ID is counted as a unique visitor. This can be incremented if an individual uses multiple devices/browsers, clears cookies, or with some privacy measures.
Adobe has some very detailed documentation for each of this. Start with this page and it will compare with the others you mentioned.
https://experienceleague.adobe.com/docs/analytics/components/metrics/occurrences.html?lang=en
