It is not incorrect to observe that all energy transfer is, ultimately, a form of work.
Work, heat, and radiation are all concepts which help us understand, quantify, and track energy. They receive different treatments because their respective mechanisms for energy transfer are different mathematically. Those treatments and other considerations evolved into the discipline of thermodynamics, which, like most emergent systems of scientific thought, is much more powerful and efficient in describing and predicting nature than first principles. But to keep our bearings we do well to observe, occasionally, that all energy is the same stuff, and it is always transferred, at some level, in association with force exerted through distance. In other words, all energy transfer is work.
What we normally identify as work is very straightforwardly the transfer of energy between objects or systems by force exerted through distance, and can be handled with a little trigonometry and multiplication.
For heating we inevitably find, at the particle level, that the transfer of energy is associated with mass is accelerated by force in collisions. Energy is transferred both ways between warmer and cooler systems. But this is a probabilistic and statistical process. It's easy to see that faster moving particles have more paths available for collisions which will transfer momentum to slower ones, than vice-versa. So in the random collisions, probability favors transfer of energy from a warmer system to a cooler one.
Radiation is a wave. All waves carry energy that was transferred to the wave by objects or particles forced to move through a distance, for instance, electrons forced to oscillate by the electric field in an antenna. It follows that energy is transferred out of the wave by forcing particles to change their motion.