Wash, peel and quarter the potatoes and add to the Instant Pot.
Add the water and salt to the potatoes.
Place the lid on the Instant Pot, ensure that the pressure release valve is set to sealing and set your Instant Pot to cook on 'Manual' or 'Pressure Cook', 'High Pressure' for 10 minutes.
Do a Quick Pressure Release (QPR) once the 10 minute cooking time has completed.
Mash the potatoes well and then add the milk and butter to the mashed potatoes and mix them in well. You may add more milk for creamier potatoes.