You can easily configure Custom Fields in your global config, whether you want to use them straightforwardly in your theming, or do something specialized with them via a custom module.

In LiveWhale 3.0+, you also have the option to add custom fields from inside a module. There’s no functionality change here, it just lets you organize your code a little differently. This is handy if you want to keep your module code completely self-contained (i.e., “Add these fields and do these things with them”), which can help for moving code between dev and prod. 

public function onCustomFields($buffer) { // when custom fields are initialized

// add one or more custom fields

$buffer['global'][]=[ // add a site-wide custom field
        'header'=>'Test Field',
        'name'=>'test_field',
        'instruction'=>'',
        'content_type'=>['events'],
        'type'=>'textarea',
        'is_required'=>false,
        'place_after'=>'tags',
        'wysiwyg'=>'limited'
];

$buffer[147][]=[ // add a custom field just to group 147
        'header'=>'Test Field 2',
        'name'=>'test_field_2',
        'instruction'=>'',
        'content_type'=>['events'],
        'type'=>'textarea',
        'is_required'=>false,
        'place_after'=>'tags',
        'wysiwyg'=>'limited'
];

return $buffer;

}