PDF Editing Issues

How to Change Underline or Pencil Color and Width in PDF on Mac and iPad

Phi Hung Vo Oct 19, 2026 869 views

Question details

The user wants to know how to adjust the visual properties, such as color, opacity, width, and style, of underline and freehand pencil annotations in a PDF.

How to Change Underline or Pencil Color and Width in PDFs on MacBook and iPad

Product: Adobe Acrobat
Device & OS: MacBook and iPad
Scenario: Customizing PDF annotations and markups to highlight text or draw freely with specific colors and line thickness on both desktop and mobile devices.
Observed behavior: Needs clear steps to locate the properties menu for underline and pencil tools across different platforms to change their visual attributes.

Before you start

Ensure your PDF document is not restricted from editing or commenting, and that your PDF reader application is updated to the latest version to access all formatting features.

Solution 1Recommended

Change Annotation Properties on a MacBook

Use the Properties menu in the desktop version of Adobe Acrobat to adjust the color, opacity, and style of your PDF markups.

Note that while you can freely change the color, opacity, and line thickness for pencil or freehand drawing annotations, underline thickness cannot be altered. However, you can change the underline color, opacity, and line style.

Select the Annotation

Open your PDF file and right-click on the existing underline or pencil annotation you want to modify.

Open Properties

Select 'Properties' from the drop-down context menu that appears.

Adjust Appearance Settings

Navigate to the 'Appearance' tab if it is not already visible. Adjust the available settings such as color, opacity, style, or thickness, then click 'OK' to apply.

Change Annotation Properties on a MacBook

Default Settings: After you change a property, Adobe Acrobat may automatically remember the new setting as the default for future annotations of the same type.

Solution 2

Change Annotation Settings on an iPad

Quickly modify the color, opacity, or thickness of your annotations directly from the pop-up styling menu in Acrobat Reader on iOS.

Advanced PDF Annotation

Easily Customize PDF Annotations with WPS Office

WPS Office provides a powerful built-in PDF editor that allows you to effortlessly add, customize, and manage annotations across different devices, including changing underline colors and pencil stroke widths.

1. Open the PDF Document: Launch WPS Office and open the PDF file you wish to annotate.
2. Access the Comment Tab: Navigate to the 'Comment' tab located on the top toolbar to reveal the annotation tools.
3. Add or Select an Annotation: Use the 'Underline' or 'Graffiti' (pencil) tool to mark up your text, or click on an existing annotation.
4. Open the Properties Panel: With the annotation selected, open the properties panel on the right side of the screen or right-click to select 'Properties'.
5. Customize the Appearance: Adjust the color, line width, and opacity settings to match your specific requirements.

Fully compatible with standard PDF formats and Adobe Acrobat files.Easily adjust the color, thickness, and opacity of underlines, highlights, and freehand drawings.Cross-platform support ensures seamless annotation syncing between your Mac, PC, and mobile devices.Intuitive, clean interface designed to maximize your productivity.

Frequently Asked Questions

Why can't I change the underline thickness in my PDF?

Standard PDF underline annotations are usually tied directly to the text font size and do not have an independently adjustable line thickness property in most PDF readers. However, you can freely change their color and opacity.

Can I set a default color for all future PDF annotations?

Yes. After customizing the properties of an annotation, you can right-click it and select 'Make Current Properties Default'. Any new annotation of the same type will automatically use these settings.

How do I remove an underline from text on my iPad?

Tap the underlined text to select the annotation, then tap 'Delete' or the trash can icon from the pop-up menu that appears to remove the underline completely.

Is it possible to change the color of multiple annotations at once?

On the desktop application, you can hold down the Ctrl key (or Cmd on Mac) to select multiple annotations, right-click to open Properties, and change the color for all selected markups simultaneously.

PDF Troubleshooting