Hi! Welcome to the community! What makes it impossible to use Spotify on your iPad? You will need to provide us with a little bit more information about your issue if you need help. Also, you should upgrade to "Premium" if you want to use Spotify on all your mobile devices.
Since the iPad is classed as a mobile device, just like all other phones and tablets, a premium subscription is currently required in order to access your playlists on that device.
If you are a US Spotify user, you can have access to mobile radio on the Spotify app for free, but for everyone else (outside of the US) you need Premium I am afraid to use any feature of the Spotify mobile app.
There lies the frustration - I don't need a Premium subscription on my desktop so why sholuld I need one on my iPad? Inconsistency and disappointment from Spotify with little in the way of an explanation.