If you want to download offline package on your Linux you can use this command
apt-get --print-uris install package_name
will give you a list of urls for packages you need to download.
sudo apt install package_name --download-only
ls /var/cache/apt/archives
wget $(apt-get install --reinstall --print-uris -qq package_name | cut -d"'" -f2 | grep "/package_name_")
sudo apt-get install devscripts
dget package_name