problem sending attachment

Hello, I used your class to send html emails with attachments that is simple and clear.

But I have problems with the function:
$ mailer-> file ("example.php");

When I load a local file with a field:
<input type="file" name="attach">

I don't know if in the function to attach the file I need to enter the temporary file or the name of the file:
$ mailer-> file ($ _FILES ['attach'] ['tmp_name']);
or
$ mailer-> file ($ _FILES ['attach'] ['name']);

You can help me solve my little doubt? Thank you Sincerely, Luke