How to make tool undropabble so player cant drop it to other player?

How to make tool undropabble so player cant drop it to other player when player press backspace tool will drop srry for my english

You don't need a script for this, well it is optional, but I'd recommend you this better way:

Go to the tool, on the properties, you will find something called "CanBeDropped". Turn the checkmark to false by clicking it.

Also you can also use @Shounak123 answer, it also works, but it's more complicated and I'd suggest you the easier way.

Put a script in the tool and paste: script.Parent.CanBeDropped = false