Pour water into pressure cooker and place steam rack in pot. Spray rack with cooking oil.
Place salmon on top of rack. Season with salt, pepper, garlic, and herbs. Cut the butter into 1/4 in. pieces and spread on top of salmon.
Close Instant Pot and lock, set vent to sealing. Set to pressure cook on manual at 5-6 minutes for frozen or 3-4 minutes for fresh.
When cooking cycle is done, do a quick release on your instant pot to release remaining pressure. Remove salmon and serve as desired with a squeeze of lemon! Refrigerate any leftovers.