1) Create a .htaccess file in the root folder of web server.
2) Put the following code in side the .htaccess file and save it.
php_value upload_max_filesize 10M
php_value post_max_size 10M
php_value max_execution_time 200
php_value max_input_time 200
Now you can upload the file-size up-to 10MB.
In these setting client can upload upto 10 MB
If he wants to increase change the upload_max_filesize variable size