Just added to the answer from Kunal Mathur and an answer to @mockash, since I cannot comment due to lack of reputation.
Before you type: pip install package_name, you need to change the directory to the folder where pip.exe is. for example:
Open Visual C++ 2015 x86 x64 Cross Build Tools Command Prompt--> change directory cd C:\Users\Test\AppData\Local\Programs\Python\Python36-32\Scripts-->Type: pip install package_name
But the weird thing is I can only successfully install via 'Visual C++ 2015 x64 x86' not 'x86 x64'