How to setup proxy?

 # cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin"
HTTP_PROXY="PROXY_URL"
HTTPS_PROXY="PROXY_URL"
NO_PROXY="localhost,127.0.0.1,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
http_proxy="PROXY_URL"
https_proxy="PROXY_URL"
no_proxy="localhost,127.0.0.0/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"