How do I fetch data from MySQL in React Native and PHP using a search engine?

this.is my php file:

$con = mysqli_connect($HostName,$HostUser,$password,$db);

 // Getting the received JSON into $json variable.
 $json = file_get_contents('php://input');

 // decoding the received JSON and store into $obj variable.
 $obj = json_decode($json,true);

 // Populate ID from JSON $obj array and store into $ID.
$ID = $obj['numero'];

//Fetching the selected record.
$CheckSQL = "SELECT origine FROM envoi WHERE numero='$ID'";

$result = $con->query($CheckSQL);

if ($result->num_rows >0) {
 while($row[] = $result->fetch_assoc()) {
 $Item = $row;
 $json = json_encode($Item);
 echo $json;
 }
}
else {  
 $EmailExistMSG= "No Results Found.";
 $EmailExistJson = json_encode($EmailExistMSG);
 echo $EmailExistJson ; 

}

And this is my react native script where i should enter number and fetch his data if it's exist in my database:

search= () =>{
     //alert('ok');
     const {numero}=this.state;

     fetch('http://192.168.1.4:80/search.php',{
     method:'post',
     header:{
     'Accept':'application/json',
     'Content-type' :'application/json'
     },
     body:JSON.stringify({numero:numero})}).then((responseData)=>responseData.json()).then((responseJson)=>{alert(responseJson)}).catch((error)=>{console.error(error);})}

  render(){
    return(

          <View style={styles.pass}>
          <TextInput placeholder="Saisir le numéro de suivi de l'envoi"   onChangeText= {numero=>this.setState({numero})}/>
          <TouchableOpacity onPress={this.search} style={{marginTop:20,marginLeft:70}}>
          <Icon name="search"  size={20}/>
          </TouchableOpacity>
          </View>

    )
  }