mkcert
Zero-config tool to make locally trusted development certificates
... in the system root store, and generates locally-trusted certificates. mkcert does not automatically configure servers to use the certificates, though, that's up to you. The CA certificate and its key are stored in an application data folder in the user's home. You usually don't have to worry about it, as the installation is automated, but the location is printed by mkcert -CAROOT.