How can I modify PDF submission attachment?

If I enable the PDF Attachment, how can I modify the format of pdf attachment?

If you want to modify the layout of the PDF submissions, you can do that using the "Customize PDF" feature under the "PDF" button in your submissions page:

Please note that this will create a FIXED PDF layout, meaning it does not adjust based on your submissions' content. It is similar to a paper print layout. Please also note that this will apply to all of your PDF submissions on that form, including the one attached on your email alert.

Once the customized PDF is created, you should be able to see it under the "Reports" drop down list where you can edit or delete it:

When you delete the PDF design under the "Reports" list, your PDF submissions' layout will revert back to the default JotForm PDF layout, the one that auto adjusts based on contents.

I hope that helps.