The first step is to add the certbot repository:
sudo add-apt-repository ppa:certbot/certbot
Next, update your package list:
sudo apt-get update
Next, install the certbot client for Apache:
sudo apt-get install python-certbot-apache
Run the following command and follow the prompts to renew multiple domains:
certbot --apache -d subdomain1.yourdomain.co.za -d subdomain2.yourdomain.co.za -d subdomain3.yourdomain.co.za