WILDCARD SECURITY

It blasts the hackers off the face of the earth with orbital lasers! killer robots sever their network connection! It's twirling a revolver on its finger while smoking three cigarettes!

And sometimes, that revolver goes off in your face, and it posts your private key on 4Chan.

They can also be gotten for free through many providers, the biggest one in self-hosting is LetsEncrypt

You have to get a certificate from a provider which can verify you control the domain.

Once you've proved control you install the signed certificate with the secret private key on your server.

You can get certificates for free via Let's Encrypt and a bunch more CA's. It hasn't been expensive for ages, unless you want fancy corporate support.