The outline color of the text cannot be changed.
The outline color varies depending on the original text color.
- For text colors of brown, red, orange, green, light blue, pink, blue, purple, gray, or black
...the outline color is "white". - For text colors of yellow, yellowish-green, or white
...the outline color is "gray".
If the background of the image or video and the outline color are blending together, please use a text color with a different outline color.
Related: Add markings and edits to images, such as arrows.
https://teachme.jp/8/manuals/4929404