You need a Google account and the Gemini app. A free personal account works, and there's nothing to install. Google says the feature is available to all users, in all languages, wherever the Gemini app is available.
You'll use the Gemini app on the web at gemini.google.com. On phones, PDF preview and editing work too. Every other format (Docs, Sheets, slides, Markdown, TXT, code) needs the web.
Chats count toward your regular Gemini usage limits, which Google doesn't publish as fixed numbers.