pip install vk_api
“PIP” is not an internal or external command executable
program or batch file.
himself came across such an error. This error occurs most likely due to the fact that PIP is not registered in Path. Try either add PIP to Path, or via CMD, going to the folder with Python, and specifically to the Scripts folder (where the Pip.exe is lying), try to install the package.
i.e. In cmd:
CD ... / python37 / scripts Pip Install vk_api.
p.s. This method is not for a virtual environment, but I think it can be done something like that.