《食品法典》有一篇文章概述了如何做到这一点：https://codex.wordpress.org/Customizing_the_Registration_Form

它甚至提供了一个示例：

//1. Add a new form element...
add_action( \'register_form\', \'myplugin_register_form\' );

function myplugin_register_form() {
    $first_name = ( ! empty( $_POST[\'first_name\'] ) ) ? trim( $_POST[\'first_name\'] ) : \'\';
    ?>
    <p>
        <label for="first_name"><?php _e( \'First Name\', \'mydomain\' ) ?><br />
        <input type="text" name="first_name" id="first_name" class="input" value="<?php echo esc_attr( wp_unslash( $first_name ) ); ?>" size="25" /></label>
    </p>
    <?php
}

//2. Add validation. In this case, we make sure first_name is required.
add_filter( \'registration_errors\', \'myplugin_registration_errors\', 10, 3 );

function myplugin_registration_errors( $errors, $sanitized_user_login, $user_email ) {

    if ( empty( $_POST[\'first_name\'] ) || ! empty( $_POST[\'first_name\'] ) && trim( $_POST[\'first_name\'] ) == \'\' ) {
        $errors->add( \'first_name_error\', __( \'<strong>ERROR</strong>: You must include a first name.\', \'mydomain\' ) );
    }

    return $errors;
}

//3. Finally, save our extra registration user meta.
add_action( \'user_register\', \'myplugin_user_register\' );

function myplugin_user_register( $user_id ) {
    if ( ! empty( $_POST[\'first_name\'] ) ) {
        update_user_meta( $user_id, \'first_name\', trim( $_POST[\'first_name\'] ) );
    }
}