One of OS X Yosemite’s new features is the Markup feature in Mail, where instead of using Preview to annotate a PDF or image before attaching it to an e-mail, you can perform these edits right in your new message. This not only adds exceptional convenience for managing your attachments in your various correspondences, but also reduces clutter and the need for odd workarounds such as printing a document to a PDF in Preview, annotating it, and then printing it to PDF again for the convenience of creating a new e-mail message with the PDF.

With Markup, if you have any document that you want to share and add annotations to, you can simply press Command-P to print it, then use the PDF menu to mail the PDF, and then mark it up before sending it off.

This feature uses Apple’s new “Extensions” in Yosemite, where developers can create a plugin to provide services to other applications. This is used for Apple’s sharing services, so for example, if a new social media site becomes popular, developers can quickly append a new sharing option for that site by adding an extension instead of relying on Apple to embed this feature in OS X.

This same approach is used for Markup; however, this does mean that in order for Markup to be used, you will need to ensure it is enabled in the Extensions system preferences (note that it should be enabled by default). When enabled, you then have two approaches for marking up attachments in Mail.

Marking up new attachments

1. Create a new e-mail message
2. Drag a PDF or image file to the message as an attachment
3. Hover your mouse over the attachment, and click the button that appears in the top-left. Note that if your attachment just looks like an icon, then the button should appear in the middle of it.
4. Select Markup from the menu that appears when clicking this button.
5. Add your desired annotations from the markup toolbar that appears.
6. Click “Done” to save and return to Mail.

Marking up attachments sent to you

Markup can only be used for items you are sending to others, so you cannot apply it to an image or PDF that someone has sent you. If you are working on a collaboration project with someone and would like to mark up an attachment they have sent you, and then send it back to them, the process for marking up the document is the same; however, you must first reply to the message and include attachments.

1. Click the Reply button
2. Click the “Include Attachments” button in the message’s toolbar (or choose this option from the View > Attachments menu)
3. Follow the above instructions for marking up the attachment.