How do I enable the remote API for dockerd

Test Docker version

ubuntu 16.04
18.01.0-ce

Create or Edit overrride.conf file 

# /etc/systemd/system/docker.service.d/override.conf
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0.0:2376

Reload the unit files and Restart the docker daemon with new startup options

sudo systemctl daemon-reload
sudo systemctl restart docker.service