Add notes and speech bubbles to a PDF in Preview on Mac
You can use notes and speech bubbles to comment on text in a PDF. These items are often used in conjunction with the highlight, underline and strike through tools.
In the Preview app
on your Mac, open the PDF you want to change.Do any of the following:
Add a note: If the Markup toolbar isn’t showing, click the Show Markup Toolbar button
. Click the Note button 
, then type text. You can use the Touch Bar, if available. To change the note colour, Control-click the note, then choose a colour. You can drag the note to a different location.Add a speech bubble: Choose Tools > Annotate > Speech Bubble, then type new text. You can use typing suggestions, if available. To resize the speech bubble, drag a blue handle.
Edit a note: Double-click a note to view it, then type new text.
Remove a note: Select the note, then press the Delete key on your keyboard (or choose Edit > Delete).
Change or remove the author name: Your macOS login name is used as the note author name by default. To change the author name, choose Preview > Settings, click PDF, then type a different name in the Name field. To remove the author name, unselect the “Add name to annotations” tick box.
View all the notes in a PDF: Choose View > Highlights and Notes (so the Highlights and Notes menu item has a tick next to it). All the notes in the document are displayed in the sidebar.
Print notes: See Print PDFs and images.