From the same page
Note: To avoid conflicts between parallel Python 2 and Python 3 installations, only the versioned pip3 and pip3.4 commands are bootstrapped by default when ensurepip is invoked directly - the --default-pip option is needed to also request the unversioned pip command. pyvenv and the Windows installer ensure that the unqualified pip command is made available in those environments, and pip can always be invoked via the -m switch rather than directly to avoid ambiguity on systems with multiple Python installations.
So try pip3
or pip3.4
in Command Prompt.
Also, ensure that environment variable are set for pip command, if you missed to opt-in for automatic PATH
configuration.