Create and Upload File in Sandbox Solution.

Hii All,

I have an office 365 site. What I needed is , I want to upload a file to the document library.  The issue is First user will fill data. And on the base of that data I need to create an html document. Do any body have idea that How can I create a file from the form data.

E.g. User will input certain data in text box and by clicking on the button, that will create a new file and stored data in to it.

Thanks.