Uploading PDF product, but only stored as INDD file. Why?

Hi,

I am giving away a data product and uploaded PDF in the product page but when I click open it, it shows a different INDD file.

It is true that this INDD is the source file that I printed the PDF, but it is the PDF that I am uploading and not INDD. SQSP does not allow PDF to upload? I don't understand why it takes the INDD while I'm definitely uploading the PDF...