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How to Underline Text in a PDF on Mac

Download Highlights for free. Not on a Mac? Checkout the iPad and iPhone guides.

1. Open the PDF document in Highlights

From the menu bar choose File > Open. Locate and select the file you want to open, then click Open:

Window for opening PDF file in Highlights on macOS 11 Big Sur

The PDF opens in a document window:

Highlights document window for macOS 11 Big Sur

2. Select the text you want to underline

This will bring up the selection popover:

3. Choose a color and click the underline button in the popover

Your annotation is added to the PDF and the text you underlined appear in your notes which you can easily share.

Similarly, you can also highlight and strikethrough text in PDFs.