Why is mysqli_query variable highlighted?

Question

PHP

Highlights a variable in the code mysqli_query($connect);
The database connection is in the connect.php file, and mysqli_query is in another signup file. At the very beginning, sign up wrote - It connects to the database, did a check, it does not give errors. Here is the connect.php code
require_once 'connect.php';

$connect = mysqli_connect('localhost', 'simply','simply' , 'tets');
    if(!$connect){
        die('Error connect to DB');
    }

Here is the signup.php code

if($password === $password_confirm){
        mysqli_query($connect );
    }

Answer 1

It's your IDE (code editor). He does not understand where this variable comes from. If everything works, then it's okay.

Answer 2

because you need to read from the beginning https://www.php.net/manual/ru/mysqli.query.php
Highlights means it asks to pass 1 more parameter
mysqli_query($connect,"SELECT * FROM blablabla" );
Well, it's better to use PDO