How to Merge PDF Files. You can do this on any computer using a free online PDF merger called PDF Joiner, or you can use a free app how to make one pdf from multiple pdfs window PDF Creator on Windows or the built-in Preview program on Mac.
Open the PDF Joiner site. It’s a teal button in the middle of the page. Go to your PDFs’ location. Click the folder in which your PDFs are stored on the left side of the window.
PDF files that you want to combine. You can combine up to 20 PDF files at once with PDF Joiner. It’s in the bottom-right corner of the window. Doing so will prompt your PDF files to begin uploading to PDF Joiner. Wait for the files to finish uploading.