How to Add a Custom User Field to the WordPress Edit User Screen?

By default, WordPress allows users to add basic information like name, email, and website URL. However, you may need additional fields to capture more personalized information, such as user preferences, or custom identifiers like a membership ID.
This guide will show you how to easily add custom profile fields in WordPress, so you can capture and store additional user information directly in the WordPress admin panel.

function ts_extra_user_profile_fields($user) {
    $extra_field = get_user_meta($user->ID, 'extra_field', true);
    ?>
    <h3><?php _e('Extra Profile Fields', 'default');?></h3>
    <table class="form-table">
        <tr>
            <th><label for="extra_field"><?php _e('Extra Field', 'default'); ?></label></th>
            <td>
                <input type="text" name="extra_field" id="extra_field" value="<?php echo esc_attr($extra_field); ?>" class="regular-text" /><br>
                <p class="description"><?php _e('Description goes here.', 'default'); ?></p>
            </td>
        </tr>
    </table>
    <?php
    // Add a nonce field for security
    wp_nonce_field('update-user_' . $user->ID, 'extra_field_nonce');
}
add_action('edit_user_profile', 'ts_extra_user_profile_fields');

function ts_save_extra_user_profile_fields($user_id) {
    // Ensure we have a valid user ID
    if (empty($user_id)) {
        return;
    }

    // Check if the 'extra_field' value is being posted
    if (isset($_POST['extra_field'])) {
        
        // Check the nonce to verify the request is coming from the correct form
        if (empty($_POST['extra_field_nonce']) || !wp_verify_nonce($_POST['extra_field_nonce'], 'update-user_' . $user_id)) {
            wp_die('Nonce verification failed.');
        }

        // Only allow admin to save changes
        if (!current_user_can('manage_options')) {
            return;
        }

        // Update user meta
        update_user_meta($user_id, 'extra_field', sanitize_text_field($_POST['extra_field']));
    }
}
add_action('edit_user_profile_update', 'ts_save_extra_user_profile_fields');