The employer needs to know the complete address of the employee for a number of reasons. One is for payroll purposes. Setting up an account for a person requires him to provide his address. Another reason is that if something wrong happens, they would know where to locate him or his family. The company also needs an employee's address so that they can be certain of his identity. And another reason would be for mailing of anything necessary purposes.
An employee form template would normally ask for the name of the person, his department or his position title. Those information are necessary so that from the list of many employees of the company, each one may be identified from the other. Part of the template would be the complete address of the employee.