How can I change the colour of the text and background of a widget?

Where did you download these themes from?

They are just available in the section appearance>themes when building a wordpress website

I am aware of that. Where did you download these themes from?

I’m confused ??
That is where I downloaded them from!

All wordpress installs come with themes as follows dependant on your version :-

Thewnty fourteen
Twenty Thirteen
Twenty Twelve etc…

So where have you got the Earth theme and Picturesque theme from?