Verify you are installing flask for your correct python version inside your virtual environment.

I’ve came across the problem:

And the first StackOverflow answer was:

But my version of flask was 1.0.2, so why I do not have the flask command?

It happened that I was installing it for a different python version inside my virtual environment (venv).

Verify your python environment for flask installations:

First find out your python version «inside your (venv)»

Installation of flask for python3

Installation of flask for python2

Installation of flask for default python (be careful if you are inside your (venv) or in your shell)