Linux Hint shows you how to get root permission in Kali Linux.
How do I get root permission in Kali Linux?
The root user name or account has default permission to all available commands and files on a Linux or any other Unix-like operating system. Kali Linux was using the root account by default till recent times. We will create a non-root user with administrative capabilities while we install Kali Linux. Other Linux distributions follow a similar procedure. The default user in older versions of Kali is root.