Can you upload forms for people to complete? or can people upload PDFs/Excel>?

We'd recommend you to create forms from scratch in the form builder so you can customize it according to your preference. If you want your users to upload files through your form, simply add a file upload field to your form. It's easy, here's how:

If you have further questions, let us know.

But, can I attach an excel spreadsheet to the form and have the respondent upload a completed spreadsheet via the form response? 

Hi,

You can add a hyperlink to your form that will allow the user to download the Excel file. However, this Excel file should be uploaded to a web server. In this way, once the user downloaded the file, they can fill it up.

You need to use the Text tool to create a hyperlink. Here's a screen animation on how to create an external link inside the form:

After filling it, they can save it and then upload it to your form. Your form should have a File Upload field on it. The user can then submit the form with the uploaded file.

Here's a guide: https://www.jotform.com/help/332-How-to-Create-File-Upload-Forms

Hope that helps. Thank you.