Upgrade to python 3.7 and pip problem.

I upgraded my python interpreter to the latest version 3.7. Prior to I was using 3.6 and all is well. I opened one of my existing projects and opened the settings dialog using menu File -> Settings. I then opened the Project node and then selected the Project Interpreter.

In the Project Interpreter pull-down I have entries for 3.6 and 3.7. If I select 3.6 I can see the packages I installed using pip. If I select 3.7 they aren't listed. I installed the packages when I only had 3.6 but I now want to use 3.7 which doesn't list the same packages I have in 3.6. So, if I switch my project to use 3.7 it fails when I run it because the packages I import aren't available to it.

My questions are:

1. Having upgraded my interpreter to 3.7 how do I run pip so that I can install the same packages as 3.6?

2. Does PC let me have packages available to both interpreters? Or do I need to uninstall everything related 3.6 and only use 3.7?

Sorry to say, I still get a bit confused how to use pip properly. Everything I do using 3.6 works 100% fine but I can't work out how to use pip or do something magical in PC that lets me have the same packages in both 3.6 and 3.7. I'd appreciated some help.

Regards.