how to forward https://www.mydomain.com to https://mydomain.com

As mentioned in the title, I want to be able to forward
https://www.mydomain.com to https://mydomain.com (or vice versa) for that matter. It seems you should be able to do it form the .htaccess file, but I haven’t figured out how.

I want to do this so that the wordpress cookies work ok. They don’t work if they are set in www and you access it from thea address without it. My users tend to use both interchangeably. Thanks again