Make the background of a text box invisible - Microsoft Support

You can remove the background and border of the text box, so that the text appears to float on top.

Add a fill or effect to a shape or text box - Microsoft Support

How to make Picture Background or Shape transparent in Publisher

Images and text boxes in PowerPoint 365 flick off and on randomly

macos - Microsoft Word Highlighting Text White - Stack Overflow

How to Find an Invisible Text Box in Microsoft Word : Tech Niche

Make a picture transparent - Microsoft Support

Add a fill or effect to a shape or text box - Microsoft Support

Set text direction and position in a shape or text box in Word

Select a shape or other object in Word - Microsoft Support

How to create a see-through text box in Microsoft Word

A Turn to Learn: Make a Transparent or Semi-Transparent Text Box

Remove Hidden Data in Microsoft Word, IT Services

Creating See-Through Text Boxes (Microsoft Word)

Invisible box randomly appeared and I can't get rid of it