The process of melting is
endothermic because you are
adding heat (or energy) to the object. When you add heat or energy to an object it begins to melt , Which tells you the object has reached its
melting point or the temperature that the object melts at.
endothermic is
adding heat or energy (
ENdothermic means
ENtering)
exothermic is
removing heat or energy (
EXothermic means
EXiting).
Conversely, the process of freezing is exothermic.
And easy way to remember this is that when ice melts it makes things cold. This is because it is sucking in the heat.