The heat from the campfire transfers thermal energy to the air with the process of convection which makes the air as seen denser and way more hotter.
The Thermal energy from the sun transfers to the solar panels with a process called radiation. the thermal energy is transferred as electromagnetic waves which cause the solar panels to absorb the energy and convert it to electricity.
The water in the pot starts off as cold but the stove transfers the energy with the process called conduction. the bottom of the pot starts to heat up which then with all of the surrounding water left heats up slowly because of the hot water around it.