Radiation -
- Heat from a fire warming hands
- Cooking popcorn using a microwave
Conduction -
- Grabbing a warm coffee mug to warm hands
- Putting an ice pack over an injury
Convection -
- An oven that cooks by cycling warm air through the bottom and out the top
- Warm water rising to the surface of the ocean and cooler water sinking
Hope that helps lol.