networking – How to add google DNS Ubuntu 18.04

Blockquote

I want to add google DNS but i can’t find the nameservers part in my config file
this is the netplan directory

netplan folder

but when i open the 01-network-manager-all.yaml to edit i can’t find name spaces part as described here
01-network-manager-

So, How can i add google dns?
Thanks in advance.