To change the color of a shape in a Synthesia video:
Navigate to the chosen video.
Select the Shape on a scene.
Click on the Fill option in the right-hand menu.
Select the new color for your shape.
Alternatively - use the Gradient option for your shape assets.
To change the color of a text (titles, subtitles, and paragraphs) in a Synthesia video:
Navigate to the chosen video.
Select the text on a scene.
Click on the Font color option in the right-hand menu.
Select the new color for your text.
Notes:
Using the Change all button in the Fill section makes all shapes/text with this color get the new one.
To learn more, check out the Synthesia Academy Feature Fridays: Shapes recording.