Attached PDF document to autoresponse emails don't seem to be attached. What to do?

Please share the form link so we can check it further.

You can also check your email alert advanced settings and make sure that the PDF Attachment is enabled and there's a PDF document selected.

Here's a guide: https://www.jotform.com/help/503-How-To-Include-Submissions-As-PDF-Attachment-In-The-Email-Notifications