How to modify or save xml on Android

I need some help. I am working on a project w$$anonymous$$ch modify some models` information and save it to a XML file. In fact ,I programmed it to load models` information from the XML in the Awake() function. I have managed to load XML file on Android with my every effort . Now, I need to know how to modify or save it . Could someone help with it ? Thank you very much!!!