Supported by some HTML5 browsers which will display a date picker

$CopyToUsbFromDate = date('Y-m-d', strtotime("-2 day", strtotime(date("Y-m-d H:i:s")))); //Get current date -2 days
//$CopyToUsbFromDate = date('Y-m-d'); //Get current date

<input type="date" name="FromDate" value="$CopyToUsbFromDate">

datetime db field from date picker

When handling form submission

  //Set datetime from date field
  $AdvertCreated = mysqli_real_escape_string($dblink, $_POST['AdvertCreated']);
  $AdvertCreated = date("Y-m-d", strtotime($AdvertCreated)) . "T00:00:00";

In the form

  <p>
  <label>AdvertCreated:</label>
  <input type="date" name="AdvertCreated" value="<?php echo($AdvertCreated);?>">
  </p>