PDF Combine is a windows PDF combiner program to combine your PDF files to a single one.

Step 1 – Add PDF Documents into the File List
Before starting the merging, you need to add your PDF files into the file list first. There are 3 ways to do that:
Method 1: Click on the “Add” button to select a PDF document from your disk and add it.
Method 2: Select and drag all your PDF files need to be combined onto the file list and drop them.
Method 3: Click on the “Add Folder” button to choose a folder contains PDF files and click on “OK” button. PDF Combine would immediately extract all PDF files from the folder and add to the file list.

Homepage: https://www.pdfcombine.net/
Download: PDFCombine-3.5-gotd.zip