What version of Ubuntu am I running?

Ask Ubuntu

• official page says lsb_release -a - listed on Description line
• hostnamectl - listed on Operating System line
• cat /etc/*release - DISTRIB_RELEASE or DESCRIPTION

useradd

No adduser so using just low-level useradd command Linuxize (advertising infested but good info)

useradd (name)

Then to check:

id (name)