Not enough space to edit content in WordPress

For some time, when I’m using WP there’s so much junk beneath the editing space that I can barely see the content that I’m managing (see image – https://bit.ly/373UTpR). I don’t have the vocabulary to even look up the proper name for all the white bars taking up space, so I had to add a new post.

What are these bars called? What did I do to invoke them? and how do I hide them so that I can work more comfortably?