How To Easily Edit PDFs using PDFpen

PDFs are in part designed so that they cannot be edited. However, often you may need to change or correct something in a PDF document. PDFpen from SmileOnMyMac is a wonderful tool that lets you do just that.

Though important, the ability to edit text is only a small part of PDFpen’s abilities. This review will investigate what can be achieved using this application; from merging pages to character recognition, as well as what could be improved.

Editing a PDF

PDFpen makes it a very quick process to edit the contents of a PDF document. It may be that you simply want to make a few adjustments to the text, or you may want to add or remove images.

To edit text in PDFpen, all you have to do is highlight the text, and then click the ‘Correct Text’ button. PDFpen will turn this static text into an editable text field, doing its best to retain the same font, size, and spacing. You are then free to type and edit the text.

Editing Text

Editing Text

You can also edit images by dragging them around inside the PDF, and adjusting the dimensions, however I have found there to be a few issues with this which I will discuss further down. Double clicking an image lets you crop it. You can also delete pictures and drop new ones in with ease.

Editing PDFs That Can’t be Edited

A brilliant feature that PDFpen boasts is the ability to turn text in the form of an image, into real editable text using character recognition technologies. For example, if you scan in a document from paper into PDFpen, you will be asked if you would like to perform Optical Character Recognition on it.



Upon confirmation, PDFpen will launch into action, decoding pixels into type. This takes only a matter of seconds to complete, after which you will have before you a text based document free to be edited.

As to be expected though, this is by no means perfect, and when I tested it on a very clean scanned document, some parts were recognized well, while other areas of the document were turned into a mess that didn’t make a lot of sense. Generally, if you only need to correct spelling, change the odd word, or search the document then this works fine, but I wouldn’t rely on it for much more until the technology is tweaked for accuracy.

Merging and Editing Pages

Creating multiple page documents is a pleasure in PDFpen. This can be as simple as just dragging individual pages from one document’s sidebar into the sidebar of another. You can also re-arrange and delete pages just as easily.

Once all adjustments are made, a quick File > Save instantly merges or updates the new PDF document.

Merging Pages

Merging Pages

Other Features

There are a few other great features worth pointing out. One of which is the ability to annotate PDFs and fill out forms easily. This can be done simply by creating text boxes and using the sufficient annotation tools. PDFpen also supports interactive PDFs, however these are not particularly common.

When using a tool such as the Text tool (for creating text boxes), double clicking the tool in the toolbar allows you to use it repeatedly without having to reselect it each time.

PDFpen also lets you sign electronic PDFs with your mouse or tablet, or import a signature from a scan in which case you can remove the white background with a transparency tool. These signatures and other graphics you may use regularly can be added to a library for quick access later.

Adding Your Signature

Adding Your Signature

PDFpen also allows you to add Notes and and Links to PDF documents, which work across other software as well. Alongside this PDFpen supports AppleScript and comes with a collection of sample scripts which can be useful for a range of purposes from splitting the PDF to numbering pages automatically.

A Few Issues

Unfortunately, PDFpen does appear to have problems with some of its features. As an example, whilst the software claims to perform proper selection of columns (that is, as you make your selection, it should move down the columns and then up into the next one, rather than straight across the page) when I first tried selecting text in columns down a PDF template I had exported from Pages, I found it was not working as it should have.

I tried selecting columns with a PDF magazine downloaded from the web, and found that it worked properly on some pages, while making mistakes on others.

Selecting Across Columns

Selecting Across Columns

As I mentioned earlier, there are also some issues with adjusting images in PDFpen. For the most part, moving images around works fine, but the big problem is that if you move an object that contains text on top of it or is a masked image, then as soon as you move it it will jump to the very top layer of the PDF or out of its mask.

This would normally be fine; just hit the Undo button. But for whatever reason when undoing these transformations in PDFpen, your layers won’t go back to the way they were unless you quit and reopen without saving. There is a ‘Move To Back’ option, but this only appears to work with layers you’ve already moved.

Finally, as I’ve said the Character Recognition is a little bit hit and miss, and the one other tiny gripe is that there can be some lag in the quality of the PDF keeping up with you as you zoom.


I’ve been impressed with PDFpen’s abilities to edit PDFs and for $49.95 (or $99.95 for a Pro version) it packs a great bunch of features. However the bugs and problems I have encountered with it are a slight let down and so hopefully the developers can find a way to fix these in the near future.

I haven’t had any experience with Adobe Acrobat so I can’t compare, but for a fraction of the price it seems to be a good alternative. Let us know your views on PDFpen, or if you use something else to edit PDFs.


PDFpen offers a simple and (relatively) inexpensive tool for editing PDF documents. The feature set is impressive, and includes the ability to covert images into text for PDF documents that are not editable by default. It's let down slightly by a few placement bugs, and issues with selection of text within columns.