Your photo shows a screen fault - colloquially known as “stage lighting”.
The “stage-lighting” issue is caused by partial delimitation of the screen backlighting. The screen is illuminated from LEDs placed around the periphery of the screen. When the fault becomes visible, you see bright patches of light around the edges of the screen.
You have two options - “repair” or outright replacement with a new iPad.
An out-of-warranty “repair” with Apple will typically cost c.60% of the “as new” price of the iPad - which may not be economically viable. Apple do not offer repairs per-se, but instead offer an exchange service for qualifying devices; the exchange will be for a reconditioned device of the same model and specification of iPad.
iPad Repair – Official Apple Support