How to merge multiple PDFs into a single file
It is probably the most requested PDF operation in the world: combining several files into a single document. A rental application (ID + proof of income + tax notice), a job application (CV + cover letter + diplomas), monthly invoicing, a report compiled from several sources… Sending one single, well-ordered file is more professional, easier to review, and often required by upload platforms that only accept one attachment.
Merging PDFs is technically simple, yet free online services often impose artificial constraints: a capped number of files, sizes limited to a few megabytes, an advertising watermark on the result, or mandatory account creation. Above all, nearly every one of them uploads your documents — identity papers included — to their servers.
This guide shows how to combine your PDFs in three steps directly in your browser, with no upload, no limits and no watermark, then how to go further: controlling file order, reorganising pages afterwards, and adding continuous page numbers for a truly professional result.
When is merging the right solution?
Merge when the recipient expects a single document: administrative bundles, job applications, platforms that only accept one attachment. Merging creates a brand-new file in which all pages follow each other — your originals remain untouched on your device. Conversely, if you only need to remove pages from one document, the Delete / Extract tool is more direct; and if you want to interleave pages from several sources, merge first, then reorganise afterwards.
Merge in three steps, nothing to install
Open the Merge tool, then drag and drop all your files at once — PDFs of any size and origin are accepted, with no cap on count or weight. Check the order in the list, adjust it with the arrows, and click “Merge PDFs”. The combined document downloads immediately, with no watermark and no advertising page. All processing runs in your browser: your supporting documents, contracts and ID papers are never sent to a server, and the tool even works offline once the page has loaded.
Controlling the file order
The list order becomes the order of the final document: the first file provides the first pages. For a job application, put the cover letter before the CV, with diplomas as appendices; for a rental application, follow the order the agency asks for. Tip: if you regularly merge the same kinds of documents, name your files with a numeric prefix (01-letter.pdf, 02-cv.pdf, 03-diplomas.pdf) — you will always add them in the right order on the first try.
Reorganising pages after the merge
Need finer control than file order? Run the merged document through the Organise tool: every page appears as a thumbnail, and you can move, duplicate or delete pages by drag and drop. It is the answer when a cover page must slot into the middle, when a supporting document is duplicated, or when a source file ended with blank pages. The “Use as input” button lets you chain merging and reorganising without re-downloading the file in between.
The finishing touch: page numbers
A merged 30-page bundle without numbering is painful to reference (“see the document on page… ?”). The Page Numbers tool inserts continuous pagination across the whole document: position (corner or centre, top or bottom), format (“3”, “3 / 30” or “Page 3”), size and starting number are all customisable. You can also skip the cover page by starting the numbering at page 2. It is the kind of detail that changes how the recipient perceives your file.
Merging and confidentiality: what to check
A rental or credit application concentrates the essentials of your administrative identity: ID document, income, address, bank details. Before using an online merge service, ask one simple question: does the file leave my device? With most services the answer is yes, with a promise of delayed deletion. Here, merging runs as WebAssembly inside your browser: not a single byte of your documents is transmitted, there is no account, no advertising cookie, no logging. Privacy is not a promise — it is the architecture.