How to increase memory limit, maximum execution time, maximum input time and maimum post size
Option a
Login to your Cpanel >> Go to "MultiPHP INI Editor"
Under Configure PHP INI basic settings, select the location which means the domain you want to increase maximum upload limit for,
Now, make changes for post_max_size and upload_max_filesize, by default post_max_size is 8M( which means 8MB) and upload_max_filesize is 2M (which means 2MB), now increase both of them to 180M, 400M, 512M, 1024, or your choice for maximum upload limit in megabyte.
Option b
Create a php.ini and place the following code in /public_html and /administrator and /wp-admin if they do exist
max_execution_time = 300
max_input_time = 300
memory_limit = 500M
post_max_size = 100M
max_input_vars = 5000