The Preview app included with Mac OS X is much more powerful than its humble name implies. In addition to simply viewing PDFs, it contains the basic PDF features an average user might need.
This is the kind of thing that would require obnoxious freeware on Windows. Even the heavy Adobe Reader PDF software doesn’t include many of these editing features because Adobe would rather push their paid Adobe Acrobat product.
Sign a PDF
Preview has a built-in feature that lets you easily sign PDFs. It allows you to capture a signature — either by signing a piece of paper and scanning it in with your webcam or by moving your finger on your Mac’s trackpad. That signature then becomes saved in Preview and you can quickly apply it to documents in the future.
To do this, click the Show Markup Toolbar button and then click the Sign button on the toolbar that appears. Use the options to capture a signature, and then use the Sign button to add your signature to documents. Your signature is applied as an image that can be dragged around and resized.
When you’re done, click File > Save to save the PDF, applying your signature to the file. You can also click File > Duplicate instead to create a copy of the PDF and save your changes into a new copy of the file without modifying the original.
Mark Up a PDF
A signature is just one of many ways Preview can apply mark-up features to PDFs. The markup toolbar offers many different tools for adding text, shapes, arrows, lines, and highlights to a PDF. Use the options to add markup formatting to a PDF, and then use the Save option to permanently apply those changes to that PDF.
As with the signing feature, the mark-up features are supposed to emulate the act of sitting down with a physical document and a pen, marker, or highlighter, scribbling all over it.
Merge Multiple PDFs
Preview is also capable of merging PDFs, which is convenient if you have multiple documents that should be part of the same file. For example, you may have scanned several pages and ended up with multiple PDFs, and you may want to combine them into a single PDF file you can send to someone so it’s properly organized.
First, open one of the PDFs in the Preview app. Click View > Thumbnails to see a sidebar with thumbnails of the list of pages in the PDF. Just drag-and-drop other PDF files from elsewhere onto the current PDF in this sidebar, and they’ll be merged into the document. You can also drag and drop the thumbnails around to rearrange the order of the pages.
When you’re done, you can click File > Save or one of the options to save your changes and get a combined PDF file.
Split a PDF
Preview also makes it easy to split a PDF file, extracting a single page of that file and saving it as its own separate PDF file. To do this, just drag-and-drop a page from the Thumbnails pane onto your desktop. You’ll get a new PDF file that just contains that page.
You can use this PDF-splitting trick with the PDF-combining one above, grabbing pages out of individual PDFs and then combining them to create a new PDF that contains just the specific pages you want.
Preview isn’t a super-full-featured PDF editor. You can’t remove elements from pages, for example. But Preview contains the basic, essential features that most users will be looking for when they seek out a PDF editor. These features are nicely integrated, although they are very easy to miss if you take Preview at its name as a barebones document-previewing application. A more full-featured application for working with PDFs is another feature Windows should copy from Mac OS X. Microsoft’s Reader app on Windows 8 isn’t very useful for desktop users.
Macs have all sorts of other useful features for working with PDFs, too. For example, you can drag multiple PDFs directly to a printer queue window to print them all at once, speeding up the printing process when you want to print many documents at once.