Ubuntu 20.04 Network Config

Identify Ethernet Interfaces
# ip a

DHCP
Create a netplan configuration
# vim /etc/netplan/99_config.yaml

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s0:
      dhcp4: true

Then Apply
# sudo netplan apply

Static IP
Create a netplan configuration
# vim /etc/netplan/99_config.yaml

network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      addresses:
        - 10.0.51.2/24
      gateway4: 10.0.51.1

Then Apply
# sudo netplan apply