Put a trivet or vegetable steamer basket in the bottom of your Instant Pot.
Pour your water into your pot.
Place your frozen or fresh corn in the cobs (ours were cut in half) into your pot and close lid and steam valve.
Set to pressure high for 3 minutes for whole cobs of frozen corn on the cob or 2 minutes for fresh corn on the cob. Do a natural release for 1 minute, then a quick release when done and serve immediately for best results.