Assistive touch button

There is a new button on my screen since my last phone update. I find it very annoying. I can move it around to get it out of the way when I’m trying to access other things on my iPhone SE. After researching a bit, it looks like it’s an assistive touch button. It was suggested that I go to settings, accessibility, and turn it off. Did that. It still doesn’t go away. Even after I shut the phone off and turn it back on.