For getting a free SSL certificate you need SSH access to your server where you installed your application code.
Then follow commands and articles which will guide you to install the necessary application.
https://certbot.eff.org/lets-encrypt/centosrhel7-apache
After installing certbot to your machine. you need to run following command to generate SSL certificate.
certbot --apache certonly --cert-name purabtech.com -d purabtech.in
