If you boil water in a pot, it can be a combination of radiation, conduction and convection.
If you have an electric hot water heater, that is primarily conduction from the heating element directly to the water.
If you have a forced air heating system, that is primarily convection once the air is heated in the furnace and blown into the room.
If you sit outside on a cool day in the sun and it feels warm, that is radiation from the sun.