WHM CloudLinux upload max size and post max size

Open /etc/cl.selector/php.conf in your preferred text editor. 

Search for post_max_size and change the default like: Range = 2M,4M,8M,16M,32M,64M,128M,512M,1G

The same can be done for upload_max_filesize and memory_limit as well. 

After saving the file with the desired changes, run the following command to force update CageFS: /usr/sbin/cagefsctl --force-update

Logout and the login in your website admin for the changes to take effect in your session.