There is no fixed definition for street photography. It's about capturing fleeting moments of everyday life, the aesthetics, the humor of the everyday and but also situations that make you think.
You can also say that street photography is a branch of documentary photography and takes place in public urban space. So sometimes photography revolves around the urban human condition. How do we live in big cities? How do certain quarters change over time?
The priority is always to treat the objects of photography with respect. You chall never uncritically show people in distress or compromising situations, no one should be put on display .
It can be interessting to depict human life in a photographic way. As it presents itself - in its ups and downs.
I is stunning and difficult to seize moments at the streets which make a portrait of our society. In addition it is nice to play with motion and shades. For street photography you can use a digital digicam with out flash. Sometimes a post-production can Street Photography make sense.