OPcache is a PHP extension, and it helps to improve the performance of your PHP Website. OPcache improves the PHP performance by storing compiled script byte code in shared memory. Using OPcache, you will find significant improvement in website loading time. It also helps to avoid load on the server. OPcache comes as a php extension in PHP 5.5 and later versions.
Note: Installing OPcache from the WHM panel will require rebuilding the Apache. It may take a few minutes to rebuild the Apache, and all the websites hosted on the cPanel will be down during this time.
1. Log in to your WHM Panel.
2. Go to software and click on EasyApache4.
3. Click on the customize button.
4. Click on PHP Extensions and select the PHP versions you want to enable the OPcache.
5. Write OPcache in the search box and click the Next button. 
6. Go to Review and click on the Provision button. 
7. You will get the below screen once it is installed completely. Click on the Done button. 
