Attach a PDF, Word document, spreadsheet, slide deck, CSV, JSON, HTML page, ZIP or source file and ask about it in the same message. The text is extracted and handed to the model as you send, so the answer is about your file. Spreadsheets come through as tables, so columns survive. If a file is too long for the model you have chosen, you are told you are getting an answer about an excerpt rather than a confident guess, and if a file cannot be read at all you are told that too. Web and mobile.