What are recommended settings for multiple iPhones and iPads in same family don't want my family members contacts in mine or them receiving texts are intended just for . Help

I don't want my wife's or children's contact information in my contacts during syncing...or them receiving texts that are intended or me.  Can someone please tell me how they handle multiple family members settings in regard to emails, iCloud, and iTunes?  Does each phone have a separate computer login, iTunes account or iCloud accounts?  Help!