As a user want to have two sites in a package, so both sites have the different record, but the user needs footer the same of both site. So he can edit those at one time. So I want to share footer between different sites.
Two sites in one package? I don’t think this is working currently, or do you mean two pages? In this case, check out http://neos.readthedocs.io/en/latest/HowTos/EditableSharedFooter.html
Sorry for the late answer, currently it’s not possible to share content between different sites. We work to improve this area, so check the changelog when we publish new version. But this is not planned for the next LTS, hopefully the next major due end of this year can help in this area.