As the leader in this industry, Adobe Acrobat provides features to highlight, underline, and strikethrough text in the PDF. With a few steps, your text will be marked up:
Step 1: Upload a PDF to Adobe Acrobat, and then select Tools to choose Comment;
Step 2: Click on the Highlight Text tool (shown as a pen) to highlight text within the PDF
Adobe enables users to change the appearance of the highlighted area, such as color and opacity.