How to merge PDF files
Merging is the most common PDF task there is: stitching a cover letter to a résumé, combining signed pages back into a contract, or assembling several reports into one file to send. The mechanics are simple, but a couple of details decide whether the result comes out the way you want.
Order is everything
When you merge, the files are joined in the order you add them — the first file becomes the front of the document and each subsequent file is appended after it. So before you click merge, arrange the files into reading order, or drag to reorder them. Getting this right up front saves you from merging, noticing page three should have been page one, and starting over.
Every page from every file is preserved exactly: text stays selectable, links stay clickable, and form fields survive. Files of different page sizes can be combined freely — an A4 document and a Letter-sized one will simply keep their own sizes within the merged file.
Merging without uploading your files
Many merge tools upload your documents to a server to combine them, which means copies of potentially sensitive files leave your computer. A browser-based merger does the work on your own device, so nothing is uploaded — which matters when you are combining contracts, financial statements or anything personal. It is also faster, because there is no upload-and-download round trip.
Once merged, download the combined PDF straight away. Since nothing is stored remotely, the file exists only on your device.