How to Change the Admin URL in Magento 2
Change Admin Path
It is not recommended to change it directly from app/etc/env.php, always prefer the CLI:
php bin/magento setup:config:set --backend-frontname="admin_path"Do not add the first / in the admin_path as it will result in an invalid parameter exception.
Change Admin URL
This can be done via the admin under Store > Advanced Tab > Admin Base URL section