Are you talking about WP text view for a WISIWYG or an actual button on the toolbar that pops up a window with the html in it.
The first is all WP and ACF does not alter that.
The second, I believe, is probably from another plugin you’re using. ACF does not add it. I know for example that TinyMCE advanced adds this button. In that case you’d need to talk to that plugin’s developer.
~JH
