How to change text in a page by utilizing a custom user id?

You could use a function like so:

function construction_intro( $id = '', $echo = true ){

    $id = absint( $id );

    switch ($id) {
        case 123 :
            $name = "Hillary's";
            $location = "Washington D.C.";
            break;
        case 9999 :
            $name = "Bernie's";
            $location = "Burlington";
            break;
        case 47679 :
            $name = "Donald's";
            $location = "New York";
            break;
        default:
           $name = "Jeb's";
           $location = 'Miami';
    }

    $text = sprintf( __( '%1$s Construction offers the highest quality Construction services to residential and commercial clients in the %2$s area.' ),
        $name,
        $location    
    );

    if( $echo ) {
        echo $text;
    } else {
        return $text;
    }
}

And then in your homepage you could call like:

<div id="intro">
    <p>
    <?php 
        $id = ( ! empty( $_GET['id'] ) ) ? $_GET['id'] : 0 ;
        construction_intro( $id );
    ?>
    </p>
</div>