ZotFile is described as 'Zotfile is a Zotero plugin to manage your attachments: automatically rename, move, and attach PDFs (or other files) to Zotero items, sync PDFs from your Zotero library to your (mobile) PDF reader (e.g. an iPad, Android tablet, etc.) and extract annotations from PDF files' and is an app in the Office & Productivity category. There are three alternatives to ZotFile for Mac, Online / Web-based and Windows. The best alternative is Highlights, which is free. Other great apps like ZotFile are PdfHighlights (Free) and Sumnotes (Free).
Highlights is a PDF reader for note takers. Highlights lets you highlight text and select images in the PDF, but take notes in a regular text-editor. No more typing notes and comments into tiny text boxes.
PdfHighlights easily extracts and exports all your highlights and annotations from all your PDF files into a single, clean report. PdfHighlights is available both as a cross-platform HTML5 web app and as a Windows application.