Please follow the below steps to increase PHP upload limits from default 2MB. The limit needs to be increased if you are uploading files (such as PDF's and images) larger than 2 Megabytes via a CMS.
Step 1: Log into the Website hosting for your domain and select the Websites and Domains tab, then click on PHP Settings:
Step 2: Under Performance settings you will need to increase both upload_max_filesize and post_max_size limits.
To adjust the maximum post size, enter a value into the select box by left clicking first.
For example for 20 Megabytes enter "20M", for 64 Megabytes enter "64M".
Step 3: Click Apply and then OK to Save the settings.