Letterheads, headers and footers: the details that identify a document
A blacked-out paragraph is not enough. See what a letterhead, a header, a footer or a fax cover sheet reveals about a sender, and how to mask it.
A letter with every name blacked out can still name its sender. The company header, a footer with a file path, or a fax cover sheet often says who sent the page. Hiding the body text is not enough if the edges of the page still talk.
Take Jane Example, a compliance officer who redacts a warning letter before sharing it with a journalist. She blacks out every paragraph but forgets the footer, which still prints her company's registration number and her own file path. The letter is not anonymous at all.
Why doesn't blanking the body hide the sender?
A letterhead is usually typed text, not a picture. Word and PDF tools store it as normal characters, so a redaction tool that only reads the middle of the page can miss it completely. The company name, address and registration number sit outside the paragraphs people usually check.
- Company name and legal form, such as SARL, GmbH or Ltd
- Registration number: SIREN and RCS city in France, Handelsregister number in Germany, company number in the UK
- Registered address, and sometimes a separate billing or plant address
- Phone number, email and website, printed in a small font at the very top or bottom
- Share capital or a VAT-style figure, when the template includes one
What must legally appear on a business letter?
Business letters are not free-form in most of Europe. France, Germany and the UK each force a company to print specific details on paper before it writes a single word of content. The rules differ, but all three make the sender traceable by law. This is a general overview, not legal advice, so check an unusual document with a lawyer familiar with your country.
| Country | Must appear on a business letter | Legal basis |
|---|---|---|
| France | Company name, legal form and capital, SIREN number, RCS registration city, registered address | Commercial Code, articles R123-237 and following |
| Germany | Legal form, registered seat, Handelsregister court and number, plus every managing director's name for a GmbH | HGB section 37a and GmbHG section 35a |
| United Kingdom | Registered company name, part of the UK where it is registered, company number and registered office address. If a director's name appears outside the letter's text or signature, every director's name must appear too. | Companies (Trading Disclosures) Regulations 2008 |
What else hides in a header or footer?
Legal wording is not the only risk. Headers and footers also carry working details nobody meant to publish, such as a saved file path, a client code or a version number. These fields update on their own, so a template built once can leak the same detail for years.
- File path, often starting with a Windows folder that includes a real username
- Client, matter or project codes used to sort documents internally
- Draft or version labels, such as Draft v3 or Internal only
- Page numbers and a printed date or time, added automatically
- The document's Author property, filled in from the software's saved settings
Microsoft's own instructions show how automatic this can be. Word's FileName field, added from Insert, then Header or Footer, then Quick Parts and Field, prints the saved file name. If the path option is checked, it prints the full folder path too, with nobody typing it by hand.
Why can a header vanish on some pages?
A header is not always the same on every page. Word's Different First Page option clears the header and footer on page one. A separate version can then be typed there, as Microsoft's own support pages describe.
That single toggle explains a common mistake. Someone redacts the footer they see on page one, then exports the file without checking page two, where the original footer still prints in full. Word also offers a Different Odd and Even Pages option, another way a header can look blank on one page and full on the next.
How do you check headers and footers before you send a document?
- Scroll every page of the finished file, not just the first one and the last one.
- Search the document for the sender's own name, domain and any C:\Users file-path fragment.
- Turn on Different First Page and Different Odd and Even Pages to see every hidden version of the header.
- Check for a fax cover sheet or a scanned header stapled ahead of the real content.
- Read the signature at the bottom of every message in a printed email thread, not only the first one.
| Where it sits | What it usually contains | Mask or keep |
|---|---|---|
| Letterhead, top of page one | Company name, logo, legal form, capital, registration number, address | Mask the registration and contact details if the sender's identity is the secret |
| Running header | Client code, matter name, a Confidential or Draft label | Mask any wording that names a client or a case |
| Running footer | File path, page numbers, printed date, Author property | Mask a file path or an author's name. Page numbers alone are usually safe. |
| Fax cover page | Sender's name and fax number, date, time, page count | Mask the sender's name and number if the sender must stay hidden |
| Printed email signature | Full name, direct phone line, job title, postal address | Mask it like any other personal contact block |
ONYRI Sanitize scans the whole page during this kind of check, header and footer included. It detects company names followed by a legal form, registration-style numbers, emails, phone numbers and addresses wherever they sit. A logo or letterhead graphic falls to the Draw an area tool instead. Its limit: a bare client code or an odd file path needs a custom rule, because nothing marks it as an ID on its own.
None of this needs to be complicated. Read every page once the mask is applied, not just the paragraphs edited on purpose. The letterhead, the footer and the fax cover sheet are part of the document too, and they often say more than the text does.
Frequently asked questions
Does removing the logo make a letterhead anonymous?
No. Most letterheads print the company name, address and registration number as normal text, separate from any logo image. A tool that blurs or deletes only the picture leaves every one of those details fully readable underneath.
Do I need to mask a director's name printed in a German letterhead?
Yes, if that person should stay hidden. Under GmbHG section 35a, a GmbH must print every managing director's surname and at least one first name on its business letters, so the name sits there by law, not by accident.
Can a header look empty on page one but still appear later?
Yes. Word's Different First Page option clears the header and footer only on the first page. The original version can still print on page two and every page after it, so check the whole file, not just the top.
What does a Word file path in a footer actually reveal?
Word's FileName field can print the saved file's full folder path when the path option is checked. On many computers that path starts with a Windows username, so a footer field can name an employee nobody meant to expose.
Sources & references
- HGB section 37a: business letters of a registered merchant (in German)Bundesministerium der Justiz, gesetze-im-internet.de
- GmbHG section 35a: business letters of a GmbH (in German)Bundesministerium der Justiz, gesetze-im-internet.de
- The Companies (Trading Disclosures) Regulations 2008legislation.gov.uk
- Mandatory mentions on French business documents (in French)Bpifrance Création
- Add the file name, date, author or other Word document properties to a header or footerMicrosoft Support
- Change or delete a header or footer on a single pageMicrosoft Support
- Field codes: FileName fieldMicrosoft Support
- Create different headers or footers for odd and even pagesMicrosoft Support