have blond hair
The German phrase 'blondes Haar haben' is used to express the idea of having blond hair. 'Blondes' is the adjective, meaning 'blond', and 'Haar' is the noun, meaning 'hair'. 'Haben' is the verb 'to have'. The phrase is used in the same way as its English counterpart.
The young woman who has blonde hair is smiling friendly.
This sentence talks about a young woman characterized by her blonde hair, who is in the act of smiling in a friendly way. The verb 'hat' (has) is used to indicate possession, here represented by the blonde hair.
My brother wants to have blonde hair, but he has dark hair.
In this sentence, the speaker's brother is described as wanting to have blonde hair, an aim contrasted by the present reality where he has dark hair. The verbs 'will' (wants) and 'hat' (has) indicate desire and possession respectively.
It is true that many actresses have blonde hair.
The sentence expresses the idea that it is a fact that many actresses possess blonde hair. Here, 'haben' expresses possession in relation to the subject 'viele Schauspielerinnen' (many actresses).