There should be a box for you to toggle between Static, ETA and mempool.
I don't get those options unfortunately. Its just a sliding scale in Electrum for Android which alters the Target (Mempool) value from lowest 10MB from the tip to 0.1MB from the tip.
I note a few of you mentioned "replaceable". How do I ensure that's enable for my transfer? There aren't any options I can see in the pay section to do this?