When you need to merge multiple PDF documents into a single file—such as combining a signed cover letter with a multipage resume—you might assume you need to purchase expensive software like Adobe Acrobat. However, if you are using an Apple Mac, you already have a powerful PDF editor built directly into the operating system.
The native macOS Preview application is capable of advanced PDF manipulation, including merging documents, rearranging pages, and deleting unwanted sections, completely for free.
Opening the Sidebar in Preview
To combine documents, you first need to configure the Preview window so you can see the individual pages visually.
- Locate your first PDF file in Finder and double-click it to open it in Preview. (If it opens in a different app, right-click the file and select Open With > Preview).
- Look at the top toolbar in the Preview window and click the Sidebar icon (it looks like a small rectangle with a sidebar on the left).
- From the drop-down menu, select Thumbnails.
A sidebar will appear on the left side of your window, displaying a small visual thumbnail for every single page currently in your PDF document.
Merging a Second PDF into the First
Once the thumbnail sidebar is open, merging a second document is incredibly simple.
- Open a Finder window and locate the second PDF file you want to add.
- Click and drag the icon of that second PDF file directly from the Finder window into the Thumbnail sidebar of your open Preview window.
- When you drag the file into the sidebar, a blue indicator line will appear between the existing page thumbnails. This line shows exactly where the new pages will be inserted.
- Drop the file on the blue line.
The pages from the second PDF will instantly populate in the sidebar, merging the two documents into one continuous file. You can drag and drop as many separate PDF files into the sidebar as you need.
Rearranging and Deleting Pages
When you merge large documents, you often end up with duplicate title pages or pages in the wrong order. You can fix this directly within the same sidebar.
- To move a page: Click on a page thumbnail in the sidebar, hold your mouse button down, and drag the page up or down to a new position in the document.
- To delete a page: Click on a page thumbnail to select it, then simply press the Delete key on your keyboard. The page will instantly vanish from the document.
Saving Your Merged Document
By default, macOS Preview autosaves changes to the original file. If you dragged a second PDF into the first PDF, the first PDF is now permanently altered to contain both.
If you want to keep your original files intact and save this newly merged document as a completely separate file, do not close the window. Instead:
- Click File in the top menu bar.
- Hold down the Option key on your keyboard. You will see the “Duplicate” option change to “Save As”.
- Click Save As…
- Give your new, merged PDF a new name (e.g., “Final_Combined_Report.pdf”) and click Save.