echo a html page and entering values into a form from php variables

I want to block access to a PHP page. I'm doing that with this way: If you been logged in, PHP check if exist a cookie, and doing echo the HTML, else it's redirecting you to login page.

Here is the code but when I'm trying to set value attribute equal to a PHP variable, I'm getting back the php code ex.""

The PHP code inside the selection tag, isn't working either!

<?php 
if(isset($_COOKIE['User_Email_Cookie']))    {
    session_start();
    $name =$_SESSION['User_FullName'];
    $phone =$_SESSION['User_Phone'];
    echo '<!DOCTYPE html>
<html>
<body>     
<h1 class="Title">Reserve a table now!</h1>
<center>
<form action="reservation2.php" method="post">
    <div class="App">
        <div class="User">
            <h2 style="text-align:left;"> Contact:</h2>
            <input type="text" id="Name" placeholder="Full Name"  value="<?php echo $name ?>" required>
            <input type="tel" id="Phone" placeholder="Phone" value="<?php echo $phone ?>"  required>
        </div>

        <div class="DatePeople">
            <h2> Choose the Date:</h2>

            <input type="date" id="Date" name="TableDate">

            <select name="Time" class="time">
                <option>19:00</option>
                <option>19:30</option>
                <option>20:00</option>
                <option>20:30</option>
                <option>21:00 </option>
                <option>21:30</option>
                <option>22:00</option>
            </select>

            <h2 style="margin-top:0px;">Choose Table, People: <a  target="_blank" href="media/diagram.png"><img src="media/info.png" width="23px"></a></h2>

            <select name="TableNum" class="table">
                <?php
                include \'connectDb.php\';  #Eisagwgi stoixeiwn gia syndesi me ti vasi
                $result=mysqli_query($con,"SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.Columns WHERE 
                    TABLE_NAME = \'available\' AND COLUMN_NAME NOT IN (\'Date\', \'Time\')");
                while($row = mysqli_fetch_array($result)) {
                    echo \'<option>\'.$row[0].\'</option>\';
                }
                ?>    
            </select>

            <input type="number" id="seats" name="People" min="2" max="8" value="4" >

        </div>
    </div>

    <div>
        <input type="submit" name="Submit" value="Reserve"> 
        <a class="button" href="logout.php">Log out</a>
    </div>  </center>
</form>
else {
    header("location: reservation.php");
}