Merge PDFs into a confidential, numbered, password-protected pack
HR files, contracts, tax papers and medical letters often go out as one pack: merged in order, marked confidential, numbered so nothing goes missing, small enough for a work mailbox that may cap messages at 10 MB, and locked with a password. Doing that in online tools means uploading exactly the files you want to keep private. This recipe does all of it in your browser and names the result with today's date.
The workflow
You addTwo or more PDFs, in order
Merge PDF
Files in input order
One file is easier to send, open and archive than a set of attachments. Put the files in order with the up and down arrows in the Input pane before running.
Watermark PDF
“CONFIDENTIAL”, diagonal, 18% opacity, every page
A faint diagonal mark tells anyone who sees a printout or a forwarded page how to treat it, while the text underneath stays readable. Change the wording in the step if your organisation uses another label.
Add Page Numbers to PDF
“1 / N”, bottom right
Numbers across the merged pack let the recipient confirm that every page arrived and refer to a page by number.
Compress PDF
Target 9,000 KB, keep text
Scans inside a pack can make it large. Many work mail servers cap messages at 10 MB, and email encoding adds about a third, so packs with scans may still need a lower target. Text-only files are already small and stay sharp.
Protect PDF
Require a password to open (AES-256)
Encryption means the file cannot be read without the password, even if the email is forwarded or stored somewhere you do not control. It comes last, so the marks and numbers are inside the encrypted file.
You set: Enter the open password.
Rename files
document-pack-2026-10-01.pdf
A neutral, dated name does not reveal what is inside, which matters for a file that will sit in inboxes and downloads folders.
You getOne numbered, marked, AES-256 protected PDF under 9 MB
A measured run
We ran this recipe on 1 October 2026 in a Chromium-based desktop browser on a Mac, with two text PDFs printed from our own documentation (2 pages and 1 page, 24.9 KB and 18.3 KB) and a four-word password.
Without the password, pdf.js (the PDF engine in Firefox) refused to open the file; with it, every page showed the CONFIDENTIAL mark and its number. Text-only PDFs are already small, so the 9,000 KB target changed almost nothing here (43.5 to 43.3 KB); it matters when the pack contains scans.
Sending the password
Send the password through a different channel than the file: a phone call, a text message or a chat app. A password in the same email as the attachment protects very little.
Choose a password the recipient can type: four or five random words are both strong and easy to read out. Toolkitta's Password Generator can make one on your device.
How to use the workflow
- Select Open this workflow, then add the PDFs in the Input pane and put them in order with the up and down arrows.
- Open Protect PDF and enter the open password. Change the watermark text if you need another label.
- Select Run workflow, then download the PDF from Rename files and open it once to check that the password works.
Things to know
- Locked input PDFs must be unlocked first. Add Unlock PDF as the first step and enter their password.
- Merging, marking and numbering rewrite the file, so an existing digital signature in an input PDF will no longer validate.
- The watermark is drawn on the pages; it labels them but does not hide or remove anything. The password protects the content, not the fact that you sent a file.
Questions
Which encryption does Protect PDF use?
AES-256, the strongest standard PDF encryption. Current PDF readers on phones and computers open it.
Is my password sent anywhere?
No. The password is used in your browser to encrypt the file, and the workflow never saves it, not even in a saved workflow.
Can I leave out the watermark?
Yes. Delete the Watermark PDF step, then open the menu on Add Page Numbers to PDF, choose Connect to… and pick Merge PDF.