Edit Minecraft flatland or height?

Can you edit the flatland on the PS4 or edit the blocks since the new uptade, is everything no longer the same as before? Please answer And also where to adjust!

You can briefly click on Editions and then go to the old version, then go to "New World" and edit the layers as you want. Then you go back to the new version and bring the edited, flat world into the new version. Tadda! There she is!