You can add fields to Posts, Users and Terms.

$box = register_cuztom_meta_box( $id, $post_type, array(
		
    'fields' => array(

        // Parameters
        array(
            'id'                    => '_data_example',
            'type'                  => 'text',
            'label'                 => __('Example'),
            'description'           => __('Field description'),
            'explanation'           => __('Field explanations'),
            'default_value'         => 'Default',
            'options'               => array(),
            'args'                  => array(),
            'repeatable'            => false,
            'show_admin_column'     => false,
            'admin_column_sortable' => false,
            'admin_column_filter'   => false,
        ),

        // Text
        array(
            'id'    => '_data_text_field',
            'type'  => 'text',
            'label' => 'Field Label',
        ),

        ...

    )

) );

id
(string) Set the ID of the field. Prefix with "_" to keep it hidden from builtin custom fields. ALL fields, including Bundles, Tabs and Accordions need an ID.

type
(string) Field type (e.g. textarea, select, radios)

label
(string) The label for the field

description
(string) Shown below the label

explanation
(string) Extra explanation. Shown below the field itself.

default_value
(string|array) Default value

options
(array) Field options, only used for select, radios and checkboxes

args
(array) Field specific args

repeatable
(boolean) Set the field to be repeatable. This makes it possible to add multiple value rows.

show_admin_column
(boolean) Show the field as a admin column in the post table

admin_column_sortable
(boolean) Make the admin column sortable

admin_column_filter
(boolean) Make the admin column filterable

Examples

Adding a field with sortable admin column

$box = new Cuztom_Meta_Box( $id, $title, $post_type, array(
		
    array(
        'id'                    => '_data_text_field'
        'type'                  => 'text',
        'label'                 => 'Field Label',
        'show_admin_column'     => true,
        'admin_column_sortable' => true
    ),

    ...

) );