How to publish using differnet user name

I would like to use different Users that I’ve generated to publish my articles so that each specific user publish a specific type of articles, I don’t want to keep switching account just to do that, is there a way I can select the user from a list and assign that person as the publisher?

If you need to see what I am working on it’s https://www.mytrendwatch.com I want different users for different category of posts. Thanks