How to make such a background + how to make a shadow on pictures?

Question

Design

For a long time I have been tormented by the question of how such cool backgrounds are made:

And the shadow on pictures of this kind:

Answer 1

LongShadows Generator
Or you can make a shadow in Photoshop the same way :) As for
the background, well, just take it and draw in Photoshop/Illustrator.
Here is a good site with patterns for backgrounds.
There is nothing special in this background, just a pleasant color in my opinion and a couple of layers thrown over with transparency.
Like this:

Answer 2

I use this action to create shadows .