I have tried to generate a provisioning profile and signing certificate with free apple developer account but can't generate it. Can I generate free apple account?
See this thread [how i can have free Developer Program ] with an already moderated link that explains Xcode's free provisioning process (with screenshots) - be sure to read all the way thru it and any updates at the bottom.
Good luck.
And since this doesn't appear to be an Enterprise Distribution question, pls. see For Best Results - Read the Label