None. I believe the current advice is breast milk or formula only.

Newborns do not need any additional water at all. All the water they need is in the breast milk or formula.

Newborns get all their hydration from either breastmilk or formula. The only exception is if it is very hot or they are sweating excessively.

They don’t necessarily need any, however if it is extremely hot and you feel dehydrated you can give them some cool boiled water in a bottle, a hydrated baby is more important that a fully fed baby. As only getting some milk and water for one feed won’t cause harm but dehydration can. Go with your gut.

Definitely none! Being so small their tummies only have room for milk

Newborns don’t need water. Breast milk and formula is usually all the hydration they need unless advised by you MCHN