Modufile's Office to PDF converter transforms Word, Excel, and PowerPoint files into PDF format using ZetaOffice — the full LibreOffice engine compiled to WebAssembly. This provides desktop-quality conversion fidelity, correctly handling tracked changes, footnotes, charts, embedded objects, complex formatting, and all the nuances that simpler converters miss. It supports DOCX, DOC, XLSX, XLS, PPTX, PPT, and their OpenDocument equivalents (ODT, ODS, ODP). The conversion engine (~50 MB) downloads once and is cached by the browser for instant subsequent use. Since everything runs client-side, your documents are never uploaded to a server — a significant privacy advantage over cloud-based converters.