If you want to install a certificate, you can install it easily using Cloudflare, that can be enabled either from the cPanel integration or signing up from dash.cloudflare.com.
Your domain name is currently using 000webhost.com, not InfinityFree. So the very first thing you will need to do is to add the domain name to a hosting account:
Doing so will not immediately fix your website, because we also don’t provide SSL certificates for your website. After you’ve added the domain to your account, you can enable Cloudflare or upload your own SSL certificate.