Blender's Python Path
Blender comes with it's own Python, which is bundled with the 3D program. When installing python dependencies, such as 'zpy' a common mistake is to install them on the system python rather than Blender's python.
More information on the install paths for Blender on various OS can be found in Blender's path documentation
If you are running Blender directly from the install folder, you can find the python and pip executables in the
On Windows, Blender's python path can be found in the program files directory
C:\Program Files\Blender Foundation\Blender 2.93\2.93\python\bin