Turn the instant pot on and activate the saute option.
Once hot, add half the oxtail and brown for about 3 minutes on both sides, remove and place on a plate. Repeat the process until all the oxtail is browned ( 2 or 3 rounds, depending on the size of the oxtail).
Do not overcrowd the instant pot, this will allow even browning.
Once all the oxtail is browned and on the plate, add and saute garlic, onions, carrots, potatoes and bell peppers for about 3 minutes. Allow the vegetables to get coated in the oxtail juice at the bottom of the instant pot.
Turn the instant pot off and activate the pressure cooker option on high for 25 minutes.
Add the browned oxtail and water. Close the instant pot and allow it to cook ( Use the Quick Pressure Release)