amolkhanorkar

For converting .key file to .pem file,

Your keys may already be in PEM format, but just named with .crt or .key.

If they begin with -----BEGIN and you can read them in a text editor (they use base64, which is readable in ASCII, not binary format), they are in PEM format.

If the file is in binary, for the server.crt, you would use 
	openssl x509 -inform DER -outform PEM -in server.crt -out server.crt.pem

	For server.key, use openssl rsa in place of openssl x509.

cecilemuller

How to create an HTTPS certificate for localhost domains

This focuses on generating the certificates for loading local virtual hosts hosted on your computer, for development only.

Do not use self-signed certificates in production ! For online certificates, use Let's Encrypt instead (tutorial).