Bek AngelaKwok You don't need anything spesific about Flarum. It is mostly about your web server's configuration.
Digital Hi @AngelaKwok , you can set it up using Let's Encrypt. Follow the instructions here: https://discuss.flarum.org/d/1623-obtain-an-ssl-certificate-and-run-your-forum-with-https-for-free Please continue the discussion on that topic.