With the help of caching it speeds up the website performance of loading the pages.
The different types are:
- Page caching: It can be used for anonymous users if it’s get enabled. It enables the entire HTML page to be stored in a database that reduces the number of queries required.
- Block caching: When block created by views, cache settings for a block in views can be set. Use block_cache_altermodule to set this for each block. The block cache settings will be used if it's enabled.
- Minimum cache Life time: Amount of time before the page cache is cleared. Page caches get cleared on each cron run.
- Expiration of Cached pages: Applies for an external mechanism like browser cache or varnish. The setting will be only in effect when the page cache is turned on.