You can stream download too which will consume significantly less resource. example:
$readableStream = fopen('test.zip', 'rb');
$writableStream = fopen('php://output', 'wb');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="test.zip"');
stream_copy_to_stream($readableStream, $writableStream);
ob_flush();
flush();
In the above example, I am downloading a test.zip (which was actually the android studio zip on my local machine).
php://output is a write-only stream (generally used by echo or print).
after that, you just need to set the required headers and call stream_copy_to_stream(source, destination).
stream_copy_to_stream() method acts as a pipe which takes the input from the source stream (read stream) and pipes it to the destination stream (write stream) and it also avoid the issue of allowed memory exhausted so you can actually download files that are bigger than your PHP memory_limit
.