My experience was so long ago, it no longer applies. Back before the internet, we had to call the publishers in New York to find out where to send materials.

The easiest thing to do today is to find a writer’s group and join it. They can give you all kinds of support and advice.

If you don’t want to do that, then visit the publisher’s website. Almost all of them have a submission guideline page that tells you how to submit your work to them.