Adding another field to user table

It’s easy. Just add function with your options to show_user_profile and edit_user_profile hooks, and save them on personal_options_update and edit_user_profile_update.

Like this for instance (you can add your own fields (text, number etc.))

/********* Additional User Content ***********/
add_action( 'show_user_profile', 'mytheme_extra_profile_fields' );
add_action( 'edit_user_profile', 'mytheme_extra_profile_fields' );

function mytheme_extra_profile_fields( $user ) { ?>
    <?php $customData = get_user_meta( $user->ID, 'custom_user_fields', true ); ?>

    <h3><?php esc_html_e('Custom option', 'mytheme'); ?></h3>

    <table class="form-table">

        <tr>
            <th><?php esc_html_e('Custom option', 'mytheme'); ?></th>

            <td>
                <input type="checkbox" name="custom_user_fields_option" id="option" value="1" <?php if(isset($customData['checkbox'])){ checked($customData['checkbox'], 1); } ?>/>
                <span class="description"><?php esc_html_e('Check for an option.', 'mytheme'); ?></span>
            </td>
        </tr>

    </table>
<?php }


add_action( 'personal_options_update', 'mytheme_save_extra_profile_fields' );
add_action( 'edit_user_profile_update', 'mytheme_save_extra_profile_fields' );

function mytheme_save_extra_profile_fields( $user_id ) {

    $userData = array();

    if ( !current_user_can( 'edit_user', $user_id ) )
        return false;

    if(!empty( $_POST['custom_user_fields_option'] )) {
        $userData['checkbox'] = intval( $_POST['custom_user_fields_option'] );
    }

    if(!empty($userData)) {
        update_user_meta( $user_id, 'custom_user_fields', $userData);
    }
}

This will give you

In the single user page (profile.php).