How to specify the source path of a local file to the server

I would like to know how to specify to the server that the route I indicated is from my computer and not from the same server, what I have is a form in html that reads a .txt file and then sends it to a php file to read the file and insert the data of the .txt in the database, doing tests in local server of apache works perfectly but when mounting it to the server it does not find the route, how could it indicate that the route is from my computer? p>

This is my form ...

<form method="POST" enctype="multipart/form-data" action="Sync_up.php">
<input type="file" accept='.txt' name="dir" id="dir">
<br>
 <p><input type="submit" value="Sync up" /></p>
</form>

and this is my php file

<?php

 echo (String)$_FILES['dir']['name']; 


 $ruta='C://Asistencias//'.$_POST['dir']['name'];
 echo "         ";
echo $ruta; 

$conexion = new mysqli("localhost", "root", "", "thinkine_SEO", "3306");

$lineas = file($ruta);

foreach ($lineas as $linea_num => $linea)
{
    $datos = explode("|",$linea);

    $id = trim($datos[0]);
    $fecha = trim($datos[1]);
    $hora = trim($datos[2]);
    $status = trim($datos[3]);

    $consulta = "INSERT INTO asistencias(idAlumno,fecha,hora,status) VALUES('$id','$fecha','$hora','$status')";
    $conexion->query($consulta);
}

?>