if($conn){
   echo "connection succesfull";
}
else{
   echo "failed";
}

//query
$query = "INSERT INTO users (user_name,user_email,user_password) VALUES (?,?,?)";
//prepared stmt
$stmt = mysqli_prepare($conn, $query);
//binding
if(mysqli_stmt_bind_param($stmt, "sss", $user_name, $user_email, $hashed_password)){
    echo "bind successfull";
   }
else{
   echo "bind failed";
    }