With the help of WP Rocket
It is used by many people because of its effectiveness and user-friendly interface. It is also considered one of the best for this process. With this plugin, you can add WordPress to the caching without facing any difficulty. By doing this, you will get a relatively better and higher speed for loading pages and sites. After activating the plugin, go to the settings section of WP Rocket and then go to the File Optimization Tab.
When you have reached there, you should find and check on the changes done for Minifying CSS files. While checking, you will see a warning about this step which can harm your website. But you have to take further steps and then tap on the dialogue which says Activate Minify CSS. If in the future you face any issue due to this, then you can always come back and then deactivate it.
With the help of SiteGround
It has features to improve the load time, which means its performance with Ultrafast PHP. Just go forward and install the plugin and then activate it. Install this on the Siteground Optimizer. When you have done this, you should tap ok on the Siteground Optimizer section of the menu which you can find on the WordPress admin’s sidebar.
You will then reach the SiteGround Optimizer section and its settings. Then tap on the Go To Frontend button, which you can see below the Other Optimizer. Then you have to change to the toggle where the option of Minify CSS files option will be visible. Again, you have to clear the cache or your WordPress website so that you can easily load the files.