How to set two lines of set title text in header?

How to set two lines of set title text in header?

Actually, I suppose what I need is a  sub-header. But, I don't see an option for that.
Looking for something like this (centered, top line larger text):

Clint  Gill
Acting Coach

You can do this with Custom CSS, do you have a text title or a logo? 

If you have a text title this should be a start:

a#site-title::after {
  content:"second title";
  display:block;
}

Further styling depends on how you want it to look. Can you share your website URL?