How to make your machine trust your self-signed certificates?

If you ever tried to set up a web application on your local machine with a secure connection (using HTTPS), you likely generated self-signed TLS certificates. When you create your own self-signed certificate, or even when the application you're using generates the certificate itself, your operating system (OS) will likely not trust the certificate. Consequently, also your other applications will not trust the certificate.

application certificate certificates generated https local machine operating system own system tls tls certificates trust web web application