WP Super Cache is available for free download in the official WordPress repository. This plugin no longer has such a sophisticated and pleasant UI, but theoretically it can be recommended even to beginners, because when you turn it on, a simple mode is activated, which turns on simple web caching.
What the plugin can do
In short: WordPress “renders” the site every time a user visits it. However, this dynamically “rendered” page can be cached to load faster on repeated user visits. WordPress basically uses this technique in several places where it operates. However, with dedicated plugins, you can further increase the level/amount of cached data.
Why this plugin is great
You can find the plugin in every WordPress site administration in the category »Plugins« and »Plugin Installation« under the name »WP Super Cache«.