There's two main places common to iPhone and iPad to access spotlight traditionally. 1) In app and 2) on the home screen. On iPad you also have 3) Press CMD + Space
Currently the situation is: -
On iPhone:
In-App - slide down for notification centre and slide right for widgets and spotlight
On home screen - Slide right for widgets and notification centre
On iPad:
In-App - Currently you cannot access spotlight in-app without an external keyboard. Sliding down and right just shows the widgets. Spotlight has not yet been added above them. I'm quite sure this is just an omission so far
On home screen - Slide right for widgets and notification centre
Anywhere: CMD + Space
So, yeah, bug/omission on iPad at the moment.