You need to modify the php.ini file from your server. You can use any FTP client such as FileZilla and follow these steps after successful login.
- Location the public_html directory that holds your site.
- Now locate for php.ini file and if you don't find then create a php.ini file and add the following details.
memory_limit = 256M
upload_max_size = 64M
post_max_size = 64M
upload_max_filesize = 64M
max_execution_time = 300
max_input_time = 1000