What converts to what
PDF becomes images (JPG, PNG, WebP), editable Word text, plain text or a PowerPoint deck, and several PDFs merge into one. Word, Markdown, HTML and TXT convert to PDF, DOCX and each other. PowerPoint becomes a PDF, slide images or text. Excel, ODS, CSV and TSV convert between each other and to JSON, YAML, XML, HTML tables or a PDF, and JSON, YAML and XML convert back to tables.
Honest limits
Browsers cannot read the old binary Office formats (.doc, .ppt), so save those as DOCX or PPTX first; the converter tells you when it meets one. PDF to Word extracts text, not layout, and scanned PDFs need OCR, which is not offered. PowerPoint slides are drawn by an open-source renderer, so unusual fonts and some charts are approximated. For exam and job portals with size limits, see the exam form tools.