Type 'start %appdata%' in cmd.
After that file explorer should pop up in '../AppData/Roaming'.
Go back one directory and navigate to 'Local/Programs/Python/Python37-32/Scripts'.
NOTE: The version number may be different so if you copy and paste the above file path it could not work.
After you do this you now have the correct location of your downloaded Python. Copy your file path by selecting the whole directory in the address bar.
Once you do that click the start icon and navigate to the Control Panel → System and Security → System. Then click "Advanced System Settings" on the left side of the panel.
Once there, click Environment Variables on the bottom right and there will be two boxes, an upper and a lower box. In the upper box: Click on the 'Path' Variable and click Edit located on the right. Click New and paste your directory Path. It should look something like this:
Click OK three times, open a new window of cmd and type: pip. See if it works.