search bar has new black box on left, font size on right, changes from full page view to single article

Starting yesterday, when I open (most) sites, as soon as it begins to open, a condensed version of the main article slides down over the page. This “new” page doesn’t let me navigate, see photos included in the original page etc. There is a new small black square with lines on the left side of my search bar, and font size icon on the right. If I click the black square, I see the original web page. But then the minute I navigate to another page, the whole thing starts again. What is this, and how do I go back to simply seeing the web page, not the condensed article version? On iPad, mac and phone!