Open the conf file under netplan directory
 
Sample config  
network:  
  version: 2  
  renderer: networkd  
  ethernets:  
    eth0:  
      addresses:  
      - 192.168.0.200/24  
      routes:  
          - to: default  
            via: 192.168.0.1  
      nameservers:  
        addresses:  
         - 192.168.0.200  
         - 9.9.9.9  
         search: \[home.mikemcfetridge.com\]