HTML in PHP [duplicate]

I want to achieve the following... I retrieve data from my MySQL database In this database I retrieve if the position is token or not if the position is taken I echo "sold" if the position is not taken I want to use a button (form) from coinpayments in my PHP

the code is like this now but I cant make it work...

    if ($row["taken"] == "no") {
    echo "<td>"
    . 
    "<form action="https://www.coinpayments.net/index.php" method="post">
    <input type="hidden" name="cmd" value="_pay_simple">
    <input type="hidden" name="reset" value="1">
    <input type="hidden" name="merchant" value="2b2a959cbc1f2d1c80eac843dd0bc14a">
    <input type="hidden" name="item_name" value="PLOT 0001">
    <input type="hidden" name="item_desc" value="Blockchain cemetery plot 0001">
    <input type="hidden" name="item_number" value="0001">
    <input type="hidden" name="invoice" value="0001">
    <input type="hidden" name="currency" value="USD">
    <input type="hidden" name="amountf" value="1.00000000">
    <input type="hidden" name="want_shipping" value="0">
    <input type="image" src="https://www.coinpayments.net/images/pub/buynow-grey.png" alt="Buy Now with CoinPayments.net">
    </form>"
    . 
    "</td>";
    }
    else
    {
      echo "<td>" . Sold . "</td>";

    }

can you guys please help me I am struggling for days now... Thank you very much!

source https://stackoverflow.com/questions/67781101/html-form-in-php