When you right-click an element on the page (and you have uBlock installed at default settings) there should be a dialog for it at the bottom.

If I right click on an item I get a block element option in the context menu. But that doesn't seem to make them persist. I usually use it to make irritating popups go away that I'm to lazy to read or that seem intentionally confusing since it is less mental load to just zap it blindly.

Thanks to all who replied. I will check the suggestions out.