Mt Everest formed due to a convergent boundary where the two continental tectonic plates (The Indian and Eurasian plates) collided and formed what we now know as Mt Everest.
How Mount Everest was formed? Mt Everest was formed by the movement of the Indian plate pushing up and against the Eurasian plate
Why was it formed? It was formed because there was no space for India to move so it went under Asia. As India keeps pushing under Asia Mt Everest grows taller and taller.