Both PDF and Word (.docx) are ubiquitous document formats, but they serve very different purposes. Choosing the wrong one can mean your carefully designed CV reflows into a mess on someone else's computer, or that a legal contract you sent cannot be properly executed. This guide cuts through the confusion with clear recommendations for every common scenario.
The Core Difference: Fixed vs Editable
- PDF (Portable Document Format) is designed as a final, presentation-ready format. The layout, fonts, images, and spacing are locked — the document looks identical on any device, operating system, or PDF reader. Ideal for sharing, printing, publishing, and archiving.
- Word (.docx) is a working document format designed for creation and editing. Content can reflow, fonts may substitute on other devices, and layout can shift between different versions of Word. Ideal for documents that need revision, collaboration, or further editing.
When to Use PDF
- CVs and cover letters: PDF preserves your layout exactly. On any device or operating system, the recruiter sees exactly what you designed.
- Final reports and proposals: Once a document is ready for distribution, convert to PDF to prevent accidental edits and lock in your formatting.
- Legal documents and contracts: PDFs can be digitally signed and certified. They are accepted by courts, regulators, and archival systems in the UK and internationally.
- Invoices and financial documents: PDF ensures figures, columns, and totals display correctly for every recipient.
- Forms for completion: PDF forms maintain layout while allowing field input. They can be locked after completion to prevent tampering.
- Published content: Brochures, eBooks, presentations converted to shareable documents — all benefit from the fixed-layout guarantee of PDF.
- Long-term archiving: Use PDF/A specifically — an ISO standard designed to remain readable for decades without relying on external resources.
When to Use Word
- Collaborative editing: Word and Google Docs (which exports to .docx) allow multiple people to track changes, leave comments, and revise together.
- Documents that will change frequently: Templates, policies, procedures, or any document that requires regular updates are best kept in an editable format.
- Mail merge: Word's mail merge capability is built around .docx — generating personalised letters, envelopes, or labels from a data source.
- When the recipient needs to edit: If you want someone to fill in a template or make changes before finalising, Word is the right choice.
- Applying for jobs when explicitly asked: Some Applicant Tracking Systems (ATS) parse Word files more reliably than PDFs for CV scanning. If the job ad says ".docx," send .docx.
Use Both: The Word-to-PDF Workflow
The best practice for most professional documents is a two-file workflow:
- Master copy in Word: Create, edit, and collaborate in .docx. This is your working file.
- Export to PDF for distribution: When the document is final, export or print to PDF. Share the PDF — not the .docx — with external recipients.
In Microsoft Word: File → Save As → choose PDF. In Google Docs: File → Download → PDF Document. This workflow means you always have an editable master while sharing a locked, professional-looking PDF.
PDF vs Word for CVs — The Definitive Answer
Send your CV as a PDF in almost all cases. Reasons:
- Your layout, fonts, column spacing, and formatting are preserved exactly as you designed them.
- No risk of the recruiter's version of Word changing your formatting.
- Bullet points, borders, and tables look identical on any device.
- PDFs look more polished and professional in most contexts.
Only use Word if the job advertisement specifically requests .docx, or if you know the company uses an ATS that cannot parse PDFs (less common with modern systems).
Editing a PDF — Is It Possible?
PDFs are not designed for editing, but limited changes are possible:
- Adobe Acrobat Pro: Can edit text, images, and pages, but complex edits often disrupt layout.
- Online PDF editors: Allow annotation, form filling, and simple text changes.
- Converting PDF back to Word: PDF-to-Word conversion tools exist but produce imperfect results — especially for complex layouts, tables, or scanned documents. If you need to make significant edits, always go back to the original Word file.
PDF Variants Worth Knowing
- PDF/A: ISO standard for long-term archiving. Embeds all fonts, prohibits encryption, no external links. Use for legal and tax documents you need to preserve for years.
- PDF/X: Designed for print production — used by commercial printers.
- PDF/UA: Accessibility-focused. Supports screen readers and assistive technology.
- Interactive PDF: Contains forms, hyperlinks, multimedia, or JavaScript. Used for fillable forms and interactive presentations.