Hello and Welcome to LinuxQuestions,
The useradd command doesn't automatically create the home directory for the user, you'll have to provide arguments to do that. To create with home directory you'd use the -d parameter. Check out the man pages for useradd.
to get a full list of the options.
If you are new to Linux try using the adduser command instead, it does a lot more automatically, like setting a home directory, setting password and such. Check out
to learn about the options of the command.