Any Linux system has a special user account reserved for a system administrator. Standard name for this account system is "root".
Please remember password for this user especially if it was automatically generated. It will be prompted if you will decide to change some system settings , e.g., to add new user accounts, to configure network or to install additional software.
Anyone who knows system administrator's password has unlimited access to your system. You can damage your system by mistake, working as a system administrator. Therefore, you should always work as a normal user, and switch to root only for administration tasks.
You can also manage SSH-keys of system administrator in server version of this module. SSH (Secure Shell) — is a network protocol that allows to organize a remote terminal access to server using a secure channel.
There are a lot of SSH clients exists, e.g., OpenSSH and PuTTY.