Question: I'm looking for a PDF annotator that allows students to collaborate on assignments and provides real-time feedback.

For a PDF annotator that lets students work on group projects and get immediate feedback, Kami is a good option. It's got more than 40 annotation tools, including multimedia resources, free templates and customizable drawing and highlighting tools. Kami also offers real-time diagnostic analytics, time-saving assessment tools and collaboration tools that let teachers see individual or group progress and offer feedback. It integrates with tools like Google Classroom, Schoology, Canvas and Microsoft Teams, so it's a good choice for teaching and learning.

Another option is Xodo, an all-purpose PDF tool that includes annotation, editing and AI-powered summarization tools. It works on multiple devices and operating systems, with secure management of PDF, Office and image files. Xodo offers several pricing levels for different needs, from basic to pro, so it's a good option for personal and educational use.

If you want AI-powered features, UPDF has a wide range of tools for managing, editing and converting PDFs. It includes AI tools like summarization, translation and chat, as well as OCR and form-filling abilities. UPDF works on multiple devices and operating systems, for personal and professional use, with flexible pricing plans.