Follow these steps

  1. 1

    Open the document

    Choose your PDF in the browser editor and scroll to the page containing the material you want to emphasize.

  2. 2

    Draw the highlight

    Select Highlight and drag across the text: the highlight follows the lines from the first word to the last. Started off the text, or with Mark set to Area in Properties, it draws a rectangle instead. Choose a color and opacity there so the content stays readable.

  3. 3

    Check and download

    Select the highlight to move or resize it. Repeat on other pages, then download a copy with the colored areas included.

Will the text under the highlight still be readable?

Yes, if the opacity is low enough. You can adjust the color and transparency before exporting the PDF.