You can set this limit in your php.ini file for your server or it can be done in an htaccess file.
The setting your looking for is;
You’ll need to up this to a more appropriate value for your product catalog and server resources - I suggest starting with a value of 128M.
If you are in shared hosting you can request support for help with adjusting this setting. If you manage your own resources you can find this file using the ‘phpinfo’ command.