unlink() function is used to delete a file.

<?php
$filename = "example.txt"; //file path
if (file_exists($filename)) {
    if (unlink($filename)) {
        echo "File has been deleted successfully.";
    } else {
        echo "Unable to delete file";
    }
} else {
    echo "File does not exist.";
}
?>

if file exist unlink()  function remove this file.