I keep finding the need to figure this certbot command out. I use it all the time but keep forgetting it and I have not been about to find a good example anywhere.

The command is:
certbot certonly --manual --preferred-challenges http -d example.com

This should be run from a command line on a local computer or could possibly be from any computer. This will give you instructions on how to validate using the certbot’s http challenge method.

The proper response from the server will need to be provided in order to generate the certs on the local machine and then the certs can be moved to the appropriate servers that have been verified by Let’s Encrypt.

See full documentation.