Hi Orestis !
Oh boy .. what is the difference between heat and temperature ?
Tricky question to answer .. it all comes back to the more basic principles and Laws of Thermodynamics and ultimately, Entropy (disorder).
In short, all Electromagnetic energy can be turned into either the sensation we relate to as 'heat', or into something we measure and call 'temperature'.
I might let others have a go at trying to explain the connection between heat/temperature and Entropy but the 'heat' we feel, is transmitted away from the fusion process inside the Sun, in the form of the Electromagnetic Spectrum (mainly Infrared).
Cheers