First of all let’s make sense of terminology.
TLS - is a more modern version of SSL.
HTTPS - is an extension of HTTP protocol with the help of SSL protocol or TLS.
Your site work through HTTPS not only protects the store from data theft but also affects SEO promotion positively.
CS-Cart allows to switch your web-store fully to work through HTTPS, however you need to purchase SSL/TLS certificate.
SSL/TLS certificate is bought for domain name and installed on server. If you use a dedicated virtual server we recommend you to contact your hosting provider for purchasing and installing certificate.
If you are an owner of dedicated server you need to purchase certificate and contact system administrator for help with installing SSL/TLS certificate.
There’s no problem to find where to buy SSL/TLS certificate. You can find many offers if you use Yandex or Google.
After SSL/TLS certificate is purchased and installed you’ll only have to enable necessary settings in administration panel CS-Cart > Settings > Security Settings: