Wash the apples by soaking them in cool water with a splash of vinegar, then rinse well. Remove damaged, soft, or moldy spots.
Place the apples in the Instant Pot, filling to about 2 inches below the top.
Add filtered water, secure the lid, and set to Pressure Cook for 10 minutes.
Let pressure release naturally for 5 minutes, then quick release. Carefully open the lid. Apples should be soft and falling apart. If not, cook 5 minutes longer.
Run apples through a food mill (medium setting), a little at a time, and collect the sauce in a large bowl.
Rinse the Instant Pot insert, return the sauce, and stir in any extras (sweetener, lemon juice, cinnamon). Set to Sauté and bring to a boil, stirring constantly, until it reaches your desired thickness. Be careful about the hot splashes!
Once ready, ladle hot applesauce into jars for canning, or let cool before freezing.