PrestaShop enables you to make some files available to your customers before their purchase. For example, let's say you sell electronics, and you would like to urge your customers to read a document on how a product works. You can upload a document for that purpose. You can also simply have the product's PDF manual directly available for download right on the product page.
Each product can have files, which can be individually set in the "Options" tab, under "Attached files". That page gives you access to all the attached files of the shop: if you need to apply the associated one file with many products, you will thus only have to upload it once.
You can also upload files on their own, before associating them with products. This is done from the "Files" page, under the "Catalog" menu.
The process to register a new file to your shop is straightforward:
You are then redirected to the list of files, where your file now appears. It is now available to all products, through their "Attached files" option. Now the "Attachments" tab will appear in your online shop and your customers can download that file if needed.