Are you referring to maximum file size upload limit (upload_max_filesize) in php.ini or maximum allowed packet for mysql (max_allowed_packet)?
To increase the file upload limit for php, just edit your php.ini and set the desired value for upload_max_filesize. You may need to restart Apache or IIS after modifying the php.ini file. To know the php configuration path, just create a new file with .php extension and write the below code:
<?phpLook at the path set for "Loaded Configuration File".
And to increase the MySQL packet, edit your my.cnf (Linux server) or my.conf (windows), and set the desired value for max_allowed_packet. You will need to restart mysql after making the changes.