By default, the
useradd utility on most Linux systems does not assign a password for the created user. Without a password on the user, the user will be unable to login / have access to most of the functionality of the desktop.
To set a password for the user, you use the following command:
Make sure to replace
<username> with your actual username (without the angle brackets). After running this, you'll be prompted to enter a new password for the user. After setting a password for the user, you should be able to login as normal.
On the other hand, Ubuntu (like all Debian-based distros) comes with the
adduser utility which is a user-friendly frontend to
useradd. Simply running the following command is all you need:
You will be shown a series of prompts, which allow you to specify the settings for the new user (username, full name, etc.), and is preferred over
useradd in modern Ubuntu versions, and unlike
useradd, you don't have to manually set a password after; part of the setup will prompt you to set the password.