Install pip install pillow error

Input: pip install pillow
error Requirement already satisfied :pillow in f:\software\python\lib\site-packages(7.1.1)
WARNING:You are using pip version 20.0.2:however. version 20.1 is available.
You should consider upgrading via the'f:\software\python\python.exe -m pip install --upgrade pip' command.

So I upgraded pip: pip install --upgrade pip
went wrong again~~
Reinstalled pip: python -m ensurpip
and then upgraded pip: python -m pip install --upgrade pip

Found: Solution: Specify the installation path
format when using the pip install command : pip install --target=target path toolkit name

success~~