Can include an attachment to a fillable PDF form?

If you mean to say you want to attach or upload a file in the fillable PDF form, that's not possible since file upload is not supported by PDF. You should consider using your Web Form for that so users can upload a file.

Thank you for your response.

Does, “using your web form” mean that I should send the form by supplying the form’s link to the user of the form? If so, can I email the link to the user, and can the user use that link each time the user want to access a new copy of the form?

The Licensing Group Ltd
6404 Wilshire Blvd.
Suite 960
Los Angeles, CA 90048
Phone: (323) 653-2700 Ext 20
Fax: (323) 556-5011
Email: danny@tlgla.com

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Yes, you can do that. Here's how to get your form URL https://www.jotform.com/help/401-Where-to-Find-My-Form-URL

For as long as the form has access to your form URL, they can fill and submit it multiple times anytime they want.