If they are scratches, then removal is not possible - short of replacing the entire laminated screen. It was possible on older iPads (non laminated) to simply replace the top digitiser screen-layer, but with laminated (more expensive) displays, the entire assembly must be replaced.
The best medicine is to ensure that you don’t scratch your expensive screen in the first place. The best option is to invest in a glass screen protector - preferably applied when the iPad is brand new. Consider this to be a sacrificial part that you can easily and cheaply replace if you scratch the screen. Remember, it only takes one spec of grit under a finger (or the tip of th Apple Pencil), to cause irreparable damage to the screen.
If your screen has a minor scratch that isn‘t too deep, investing in a glass screen protector after the damage has occured might help to disguise the scratch. If the scratch is very minor, then the adhesive layer on the back of the screen protector might conform and help fill the scratch - providing a cosmetic fix. If you can feel the scratch with a fingernail, you may be out of luck.