Inserting headers in the articles....

Hi there -

I feel like this is a dumb question - but I can't figure out how to get in HTML view for my posts in the backend, or just easily change some of the text to H1, H2, etc. We are migrating over content, so the headers are with the body copy. I'm thinking there must be an easy to make certain texts headers, but only see the ability to change font size from the panel on the right. I'm probably missing something very obvious... any thoughts?

Thanks,
Kevin