Cowork · Lesson 03 Pro ~13 min read docx, xlsx, pptx, pdf

Documents: from prompt to .pptx in one step.

Cowork's biggest practical win is creating Office-quality documents from scratch. Through a system called Skills, it can produce real .docx, .xlsx, .pptx, and .pdf files — not chat-and-copy-paste. This lesson covers the four formats, the prompts that produce professional output, and the things you need to specify upfront for the result to actually be useful.

The mental model

Cowork doesn't copy-paste. It builds real documents.

When you ask ChatGPT to 'write a report,' you get text in the chat that you then copy into Word and reformat. When you ask Cowork to write a report, it produces an actual .docx file in your folder — with proper headings, a table of contents, page numbers, formatted tables, embedded images. Same for Excel: real formulas, multiple sheets, conditional formatting. PowerPoint: layouts, speaker notes, consistent design.

This is possible because Cowork has 'Skills' — bundled toolkits that know how to build each file format properly. You don't need to know they exist; you just ask for the output format and Cowork picks the right Skill.

The implication for your prompts: be specific about format choices upfront. 'Make a report' is vague; 'make a 6-page Word doc with a cover page, table of contents, three sections, and an appendix' produces dramatically better output.

Workflow 01 Word documents that look professional

1

Build a polished Word report from notes

Most reports are written in Word. Cowork's docx Skill handles styles, headings, page numbers, and even table-of-contents generation. The pattern is to give it the raw content (notes, data, sources) and specify the structure.

The prompt that works

Word report patternBuild a Word document called 'Q1-marketing-review.docx' with these sections: 1. Cover page (title, my name, date) 2. Executive summary (1 page max) 3. Channel performance review (one section per channel: SEO, Email, Paid Social, Content) 4. Wins and lessons (bulleted list) 5. Q2 recommendations (numbered list) 6. Appendix with the raw data tables My raw notes and the data are in 'q1-data.xlsx' in this folder. Use proper Heading 1/Heading 2 styles, page numbers in footer, table of contents on page 2. Save as .docx with track changes off.

Best use cases

  • Quarterly business reviews
  • Project post-mortems
  • Customer case studies
  • Internal training documents
Always specify file extension (.docx) and explicit structure. 'Write a report' produces text in chat; '.docx with these sections' produces an actual file.
Time savings: 20-page report: 4-6 hours manually → 30 min with Cowork drafting + your review.

Workflow 02 Excel sheets with real formulas

2

Build spreadsheets that calculate, not just display

Cowork's xlsx Skill builds real Excel files with working formulas, multiple sheets, formatted headers, and conditional formatting. The key prompt insight: be explicit about whether you want values (static) or formulas (live).

The prompt that works

Excel with live formulasBuild an Excel file called 'budget-tracker.xlsx' with these sheets: 1. 'Income' — columns: Date, Source, Amount, Category. Pre-fill 12 rows for the last 12 months. 2. 'Expenses' — columns: Date, Vendor, Amount, Category. Pre-fill 50 rows. 3. 'Categories' — list of valid categories for both Income and Expenses (use data validation to enforce). 4. 'Summary' — pivot-style summary with SUMIF formulas (not pasted values): total income, total expenses by category, net by month. 5. Conditional formatting on the Summary sheet: red if net is negative, green if positive. Use the Currency format ($X,XXX.XX) for all amount columns.

Best use cases

  • Budget trackers and financial models
  • Project plans with Gantt-style status
  • Sales pipeline trackers
  • Inventory or asset tracking
If you don't say 'use formulas, not pasted values,' Cowork sometimes pastes static numbers. The formula-first instruction matters.
Time savings: Complex spreadsheet from scratch: 2-3 hours → 15 min.

Workflow 03 PowerPoint decks with real layouts

3

From outline to finished slide deck

PowerPoint is the slowest of the Office formats to build manually because each slide is a layout decision. Cowork's pptx Skill handles slide layouts, title hierarchy, bullet patterns, and even speaker notes. You provide the outline + key data; it builds the deck.

The prompt that works

Slide deck from outlineBuild a PowerPoint deck called 'q1-review.pptx', 12 slides, using these section headers and content. For each section, suggest the right slide layout (title, bullets, two-column, chart, image-heavy, etc.) and include 1-3 sentences of speaker notes per slide. 1. Title slide: 'Q1 2026 Marketing Review' + my name 2. Agenda 3. Channel mix (data in q1-data.xlsx — chart) 4-7. One slide per channel (text-heavy, key results + commentary) 8. Top wins (bullets) 9. Top misses (bullets, more concise tone) 10. Q2 plan (numbered list) 11. Asks for the team (bulleted) 12. Thank-you / Q&A Use a clean theme: dark text on light background, sans-serif font, consistent color palette. Don't add stock photos or clip art.

Best use cases

  • All-hands or team-update decks
  • Customer presentations
  • Investor or stakeholder updates
  • Training material
Slides are the format where iteration matters most. Plan to do one Cowork-generated draft, then refine specific slides by hand. The deck is 80% done, but the last 20% is your taste.
Time savings: 12-slide deck: 3-4 hours → 45 min including refinement.

Workflow 04 PDFs: extract, combine, generate

4

PDF operations that aren't painful for once

Cowork's pdf Skill handles the operations that PDF workflows usually struggle with: extracting text or tables from a scanned PDF, combining multiple PDFs into one, generating a new PDF from content, and filling form fields.

The prompt that works

Multi-PDF workflowI have a folder of 15 scanned contract PDFs. For each one: 1. Run OCR if needed so the text is searchable 2. Extract the parties' names, effective date, and contract value 3. Save each extracted result as a row in a CSV called 'contracts-summary.csv' 4. Combine the original 15 PDFs into one master PDF called 'all-contracts-2026.pdf' with bookmarks at the start of each individual contract If OCR fails on any PDF, flag it in a separate column.

Best use cases

  • Legal contract summarization across many files
  • Combining receipts into one PDF for expense reports
  • Generating filled PDF forms from a CSV of data
  • Splitting a multi-page PDF into individual files by section
OCR on bad scans is hit-or-miss. Cowork won't invent text it can't read — flagged 'unreadable' entries are honest, not lazy.
Time savings: 15-contract review: 4+ hours manual → 20 min.

Build the document you've been avoiding

Think of the most tedious document you need to make this week — a report, a budget, a deck. Use the appropriate Cowork pattern above. Get the 80% draft in 15 minutes, then refine the last 20% by hand. Note the total time vs. what you'd estimate it would have taken manually.

Back to Claude Mastery → Try a prompt in the playground →

What you can do now

  • Specify the exact file extension (.docx, .xlsx, .pptx, .pdf) in every prompt
  • Provide explicit structure — sections, sheets, slide count
  • For Excel, instruct 'use formulas, not static values' when you want live calculation
  • For PowerPoint, accept the deck as 80% done and refine the last 20% manually
  • Save outputs to new filenames, never overwrite the source data
Pro+
Up next in Claude Mastery

Lesson 04 · Email + calendar: Outlook, M365, scheduling automation

Connect Cowork to Outlook and your calendar via MCP. Now Cowork can draft replies, search your inbox, surface meetings, and schedule things. The patterns that turn email from a time sink into a 15-minute morning ritual. See the track →