how to do an "interface" for members

Hello.
maybe someone can help me.
I can not find information on how to do an “interface” for those members who want to assists in the developmental site with information like site events.
to be more explicit, I want to create a page that is strung elements to be complemented by a contributor (text, photos, location, date etc.) without the one who introduced the above information to be logged in wp panel .
thank you