Egg Noodles and pappardelle noodles are similar but not the same.
The difference between pappardelle and egg noodles is in the ingredients that makes them.
With egg noodles the milk and butter are added as ingredients however with pappardelle noodles they do not contain any butter or milk in the ingredients.
Egg Noodles are also larger and thicker in size than pappardelle are.
But if your recipe calls for either pappardelle or egg noodles you can use either one.
But the taste will be different and you'll either have larger or smaller size noodles.
For some people that would make a huge difference but for others it may not.
However if you're serving the food to paying customers then you would want to use the correct noodles but at home it does not matter as much.