How to install install an Intermediate/chain certificate?

I created SSL on Cloudflare and installed it on my cyber panel website. But the browser shows the website is unsecured

so I did a test on and the result showed “The certificate is not trusted in all web browsers. You may need to install an Intermediate/chain certificate to link it to a trusted root certificate”.

currently, I can not apply for let’s encrypt SSL because I got a limit of one week, that’s why I am using Cloudflare SSL.

what type of ssl of having in Cloudflare make it flexible otherwise if your site didn’t have r3 certificate it will not work

How can I get that?

if you use cloudflare
just turn on the proxies but my suggestion
to not turn on proxies for hostname/mail server hostname