Certbot
Installation​
Add certificate​
This will request a certificate and install it onto all nginx sites that use these domains.
certbot --nginx -d example.com,www.example.com
List certificates​
certbot certificates
Modify certificate domains​
Run the same command with --cert-name to make sure cerbot won't request a new certificate.
certbot --nginx --cert-name $name -d example.com,www.example.com,newsubdomain.example.com
If certbot asks you, press e to expand or u to update the certificate.