many business iphones- need business apple id

What is the best approach for establishing and using a business apple id for all the iphones in our company that are company owned? Right now everyone uses their own and when an iphone is returned by an employee, it might still be linked to their apple id and I can't erase it for the next employee to use. I would like to avoid this dilema by having a company apple id. But I don't know where to start...

Thanks

Pam