auf letzten Stand:

py -m pip install --upgrade pip

Modul per pip installieren (hier opencv)

py -m pip install opencv-python

Collecting opencv-python
  Downloading opencv_python- (24.2 MB)
     |████████████████████████████████| 24.2 MB 6.4 MB/s
Collecting numpy>=1.17.3
  Downloading numpy-1.19.0-cp38-cp38-win32.whl (10.9 MB)
     |████████████████████████████████| 10.9 MB 3.3 MB/s
Installing collected packages: numpy, opencv-python
  WARNING: The script f2py.exe is installed in 'E:\appli_stat\Python38\Scripts' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed numpy-1.19.0 opencv-python-