From the start menu search for “Edit environment variables for your account”

Click Path and then Edit.

Then click new and paste in the path to the ADB directory which should be

%USERPROFILE%\AppData\Local\Android\sdk\platform-tools

And hit OK

You should be good now. You’ll need to relaunch and Command Prompts you have open, but you should be able to run adb without having to navigate to the adb folder.