Could you please give me the reasons why do we wear a Kippa? Please include also sources from the Torah, G’mara, etc. Thanks.

There is no mention of the need to cover ones head in the Torah. The Talmud describes a few Chassidim who took it upon themselves to cover their heads. The musar point of view is that out of respect one should during prayer and before important people not stand bareheaded. Throughout the generations it has been accepted and has become an obligation. Rabbi Ro’I Margalit