You can also preview what the merged documents will look like. You have the option to move them up or down, or sort by name. If you just need to merge two documents without changing the order of any pages, choose Merge. It's available through the Microsoft Store for free. We tested a few, and found a solid option in PDF Merger & Splitter by AnywaySoft.
If you're using Windows, you'll need a third-party app to help you combine PDFs.
