Error when installing offline whl

I don't have the click package needed for flask, so it's an error.

Python packages have dependencies, so you can copy and install them together.

pip download flask

If you do, you will probably receive flask and dependent package whl together. You can copy it all, take it, and install it.

Copy all installation files to an empty directory,

pip install *

Try it.

If there is an error, you can install it upside down one by one.

pip install click 

You can install it first.

I solved it. As you said, pip install* had an error and installed each one. SSL authentication error occurred during additional pip download command. Resolved with the --trusted-host pypi.org option. Thanks once again.