How to Annotate a PDF on Mac With Preview

Reviewing a contract, grading a paper, marking up a design spec — Preview handles all of it. Its annotations are standard PDF annotations, so what you add shows up in Acrobat, in browsers, and on the sender's Windows machine. Here's the toolbar tour and the habits that make review work fast.

Open the markup toolbar

Open the PDF in Preview and click the markup button (the pencil-tip circle in the toolbar), or choose View → Show Markup Toolbar (Shift + Cmd + A). A second row of tools appears: selection tools, sketch and draw, shapes, a text box, a signature button, and style controls for color and line weight. Everything below lives in this row, and the same commands are in the Tools → Annotate menu if you prefer menus.

Highlight, underline, strike through

The highlighter is the one tool that works without the markup toolbar: select text and press Ctrl + Cmd + H, or click the highlight button in the main toolbar. Its dropdown arrow holds the options:

• Five highlight colors — pick one before you select, or select text first and then choose. A color-per-topic system (yellow for facts, green for action items) survives export and reads clearly on the other end.
• Underline and Strikethrough — same dropdown, same select-then-apply flow. Strikethrough plus a note beside it is the classic "delete this" edit.

To remove any of these, click the highlighted text and press Delete, or right-click it and choose Remove Highlight.

Notes, text boxes, shapes, and arrows

• Note (Tools → Annotate → Note) drops a sticky note that collapses to a small yellow square. Double-click to read or edit. Notes are the right tool for comments — they don't cover the page, and other PDF readers show them as comment icons with your text intact.
• Text box puts words directly on the page — best for filling gaps or labeling, not for commentary. Set the font and color with the style buttons at the toolbar's right end.
• Shapes gives you rectangles, ovals, lines, and arrows. An arrow plus a note is the fastest "this, right here" gesture in a review. The shapes menu also hides a loupe that magnifies a region — useful for pointing at fine print.
• Sketch smooths your freehand stroke into a clean line or shape and offers the original squiggle as an alternative; Draw keeps your stroke exactly as drawn.

Every annotation stays editable until you flatten or print the file: click one to move, restyle, or delete it. Tools → Show Inspector → the annotations tab lists them all, which is the quick way to audit a long document before sending it back.

How your marks travel

Preview writes standard PDF annotations, so Acrobat, Windows readers, and most browsers display them and list your notes in their comment panes. Two caveats. First, anyone with a PDF editor can delete annotations — a highlight is commentary, not security; if you need content gone, that's redaction. Second, a few minimal viewers render notes as icons only, so for a recipient you can't predict, put decisive comments in the email as well. When the marks must be permanent — a graded paper, for example — File → Print → PDF → Save as PDF flattens everything into the page image.

Two habits make review sessions faster. First, duplicate before you begin (File → Duplicate) when the document belongs to someone else — you'll want a clean copy if the markup goes sideways. Second, learn the one shortcut that matters: with text selected, Ctrl + Cmd + H highlights without touching the mouse, so a read-through becomes select, key, keep reading. Everything else can stay in the toolbar.