How to change color of bar chart?

The plot style shows a Color Palette. You can grab any of the colors and move it. The color which is shown first defines the color of your bars. In other charts which use several colors, the colors will be used from left to right, so rearrange the colors to your liking.

Hi,

And in addition to what jacob has already said, you can left-click on any color to change it to anything else, you can add new colors into the palette, and you can remove colors from the palette by right-clicking on them.

Regards,
Marco