Install LetsEncrypt Ubuntu
sudo apt-get update
sudo apt-get install letsencrypt
Add a domain .conf file in NginX of Apache2 if needed
/etc/nginx/sites-available/ or /etc/apache2/sites-available/
cd /letsencrypt
Add Cert for www.domain.com
sudo ./letsencrypt-auto --server https://acme-v01.api.letsencrypt.org/directory -d www.domain.com -d domain.com
Add Cert for subdomain
sudo ./letsencrypt-auto --server https://acme-v01.api.letsencrypt.org/directory -d static.domain.com
Renew Cert:
sudo ./letsencrypt-auto renew --server https://acme-v01.api.letsencrypt.org/directory