This question has a few parts:
1) What type of kinyan is used in mechirat chametz and how does it work?
2) What elements need to be in the document for mechirat chametz?
3) Can one sell the chametz to a woman non-Jew or must it be a man?
Please send sources.
1) A better question is: “what type of kinyan isn’t used in mechirat chametz?” In principle, the document between the rabbi and the non-Jew includes virtually every possible kinyan in the book, including chalipin, agav karka, odisa, and kessef.
2) I don’t know which document you mean. In the document between the homeowner and the rabbi, there is only a need for a basic specification of the type of chametz involved and its location. Some say that the value of the chametz should also be specified. A contact number is also good. The most important part of the document is that the homeowner appoints the rabbi as his envoy to sell the chametz. The document between the rabbi and the non-Jew, however, is more complex, and includes all of the kinyanim mentioned above.
3) There is no problem to use a woman.