package com.test.application;

import com.android.volley.Response;
import com.android.volley.toolbox.StringRequest;

import java.util.HashMap;
import java.util.Map;

public class RegisterRequest extends StringRequest {

private static final String REGISTER_REQUEST_URL="http://www.mywebsite.com/Register.php";
private Map<String,String> params;
public RegisterRequest(String user, String password, String email, Response.Listener<String> listener){
    super(Method.POST, REGISTER_REQUEST_URL, listener, null);
    params = new HashMap<>();
    params.put("name", user);
    params.put("password", password);
    params.put("useremail", email);
}

@Override
public Map<String, String> getParams() {
    return params;
}
}

<?php
    $con = mysqli_connect("bbdd.mywebsite.com", "user", "password", "database");

    $Username = $_POST["name"];
    $Password = $_POST["password"];
    $UserEmail = $_POST["useremail"];
    $statement = mysqli_prepare($con, "INSERT INTO AccountsInfo (Username, Password, UserEmail) VALUES (?, ?, ?)");
    mysqli_stmt_bind_param($statement, "ssis", $Username, $Password, $UserEmail);
    mysqli_stmt_execute($statement);

    $response = array();
    $response["success"] = true;

    echo json_encode($response);
?>