Problem in enabling caching in WordPress?

Dears,

I’m trying to enable caching for a WordPress website. I tried use the mod_expires on the .htaccess file & it didn’t work.

I also tried to use the “WP Super Cache” plugin. I went through some of its settings & the plugin says it works. But when I use Google page speed test it fails and says it still needs the cache to be enabled.

I need help please…