In the event you need to edit your PHP on your VPS or Dedicated server, you will need to access the WHM in order to do so. Editing the php.ini will not help you. So log into your WHM: How to Access the WHM
Once in the WHM go to the search bar in the top left and type PHP.
Then go to PHP Configuration Editor
And there you are. Click on Advanced mode to get the full list, such as post_max_size
When you are done go to the bottom and click on save.