fatal error oci_connect

Hello, I'm starting my studies in this area, sorry if you ask some nonsense question !!

I have an oracle database that is in a virtual machine, and I'm doing a university job and I would like to connect this web system to this bank .. so my doubts, do I need to install some application on the physical machine? because I'm doing my php code as follows:

$ora_senha="1234";

$oracle_bd="(DESCRIPTION=
                (ADDRESS_LIST=
                    (ADDRESS=(PROTOCOL=TCP)
                        (HOST=10.0.0.10)(PORT=1521)
                )
            )
            (CONNECT_DATA=(SERVICE_NAME=teste))
            )";

if ($ora_conexao = oci_connect( $ora_usuario, $ora_senha, oracle_bd) ){
    echo "conexão com o banco oracle foi feita com sucesso";
} 
else
  echo "erro na conexão com o banco";
?>

but oci_connect (); does not connect in any way always gives the following error:

  

"Fatal error: Call to undefined function oci_connect () in"

I already did everything, uncommented the extensions in php.ini already downloaded the file instantclient but always of that error !! Someone please have one. Thanks in advance for your help!