If you don't already know the proxy in use (in your company), read the post Find out Proxy in Use to figure it out.

Put the following lines into your wget configuration file, which is usually ~/.wget.

use_proxy = on
http_proxy = http://username:password@proxy_ip:port
https_proxy = http://username:password@proxy_ip:port
ftp_proxy = http://username:password@proxy_ip:port

Use wget to download files. A illustration is given below.

wget --no-check-certificate --load-cookies=/home/mobaxterm/ff_cookies.txt -p https://bitbucket.org/dclong/config/get/master.zip

You have to use the --no-check-certificate option if you encounter "certificate verification" errors. Another way to do this is to set environment variables http_proxy, https_proxy and ftp_proxy etc.