The only remedy for a cracked or broken iPad screen is replacement of the screen - or the iPad.
A cracked or damaged screen may be hazardous - as glass shards may detach from the screen and/or liquid crystal material (an irritant) may leak. When damaged, the screen is also likely to malfunction or be insensitive to touch. You might apply a plastic film to prevent fragments of glass from detaching from the screen, but this is not a substitute for repair.
You can check availability/eligibility for repair - and associated cost for your country/region - here:
iPad Repair & Service - Apple Support
In addition to Apple's mail-in repair service, you can arrange repair at the Genius Bar of your local Apple Store or Apple Authorised Service Provider (AASP):
Genius Bar Reservation and Apple Support Options - Apple
For practical purposes, in lieu of repairing and returning your own iPad, Apple usually exchange the iPad for a renewed/refurbished iPad of the same model and specification. The cost of the exchange is the same as would otherwise be charged for repair. Unless you have benefit of an active AppleCare plan, an out-of-warranty repair while expensive will be somewhat less than the cost of a replacement iPad.
If you have an active AppleCare+ plan, the cost of repair is reduced to a small excess/deductible fee.