From SwiftKey 1.6.3 onwards we've made it possible to control your SwiftKey cursor using 3D Touch.
3D Touch is triggered by pressing down firmly in the keyboard area. You can then move your finger to reposition the cursor.
If you've got more than one line of text, sliding your finger vertically up and down will not change lines. Instead you'll need to move your finger horizontally left and right, to the end of the line, to advance up and down.
You cannot initialise 3D Touch by pressing down on the Backspace key.
Note: 3D Touch is only available on certain devices, namely iPhone 6s or later.