Please, pay attention to our new moduleAdvanced Downloads. The Easy File Attacher will no longer develop.
OCMOD extension Easy File Attacher adds a tab "Downloads" to product form and allows to easy upload and attach one or more files. You can attach a file by direct link.
+ attach one or more files from new tab "Downloads" in the product form
+ attach file by direct link
+ downloads field in the links tab is hidden
+ autocomplete (you can attach existing downloads) + Extension supports English, Russian and Ukrainian. English only from 1.3 (See readme file if you want to add your language)
+ 1.5 supports Russian
+ compatible with Opencart3
Also, you can use a free extension Downloadable files with Easy File Attacher to show downloads list on the product page.