There is no Polish version of that name. You can just say Jennifer.
"Jennifer"
Jennifer or Gennifer
in polish : Edward [edvard]
it's not a Polish word.
In Polish safety is "bezpieczeństwo".
In Polish Natalie is "Natalia".
it's not a Polish word.
In Polish winter is "zima".
You Spell It as Warszawa.
In Polish Sandra has the same letters as in English, so you simply spell "Sandra".
Ryan in Polish is spelled "Ryjan".
Richard in Polish is Ryszard.