How to get Drush in my path in Windows 10?
The variable will be "Path". Just select that one and edit it then add new line.

You have to download the drush.phar file from here: https://github.com/drush-ops/drush-launcher/releases/tag/0.6.0

Then you have to change the file name from 'drush.phar' to just 'drush' and put that file somewhere and that location needs to be in your path. I put mine in both my system path and user path. Once that is done you shoud be able to call drush from your drupal directory if it was installed with composer.