On an iPhone, I was writing text. Among the keys, I have seen arrows for moving the cursor right and left.
How can I have these keys on iPad ?
These would be very useful.
Why aren't these keys present on iPad ?
At this point, there is no default functionality on the iPad for arrow keys. (I suppose the idea is to tap the text to position the arrow). There is a chance that there is a 3rd-party keyboard for iPad that would include arrow keys.
Those arrow keys, from what I have seen, are unique to the iPhone 6 (and Plus) while in landscape mode.
Because of the way that the iPad can be typed on (two-handed vs. two-thumbed on the iPhone), there is a chance that arrow keys will never be brought to the iPad's default keyboard.
Try holding two fingers at same time anywhere at virtual keyboard and you should be able to move cursor / marker left - right (keyboard letters become invisible in the meantime) using ios 9.x.x.