The maximum file upload limit depends on the hosting type, OS, and Control Panel you are using. It also depends on the core server with the location of the PHP.INI file, and its setting.
Basically, this is not a single line change. This would require the customization of PHP parameters or value as a whole, which means that, unfortunately, you can’t increase the upload limit from within WordPress. However, with the Control Panel, you can modify the PHP settings.
If needed please contact your hosting provider.