How the Himalayan Mountains were formed was tectonic plated movement and subduction zones. What plates that were involved were the Indo-Australian plate and Eurasian Plate. The Indo-Australian plate was triggered about 40 to 50 million years ago. It traveled approximately 15cm per year.
You might ask how did the plates form mountains by pushing into one another? Well how it worked was the Indo-Australian plate was forced under the Eurasian plate and pushed molten rock other words know as magma and forced it up-ward. This is known as a subduction zone. Only a portion of the Himalayans were formed by this subduction zone due to the Indo-Australian plate had high counts of enormous quantity of light quartz-rich rocks which the Eurasian plate also had. When these parts of the plates hit one another they sky rocketed which formed what is what modern day Himalayan mountain range.
Mount Everest is one particular mountain in the Himalayan mountain range because it is the largest mountain in the world (above sea level). This mountain was one that was formed from the plate collision when the plates pushed one another up (rather than subducting). Scientists believe that the mountain is growing 1 cm per year due to the Indo-Australian plate stretching.
The Himalayan mountain range was formed in these five stages.
One the Indo-Australian plate moved northward towards the Eurasian plate. This is believed to happed from the convection inside the mantle of the earth. The second stage of the formation of the Himalayan mountain range is the collision of the plates, which was the start of the next two stages. The third stage was when the plates subducted and force the magma up. Fourth was when the plates hit light quartz-rich area of the plates colliding. And finally, fifth, the indo plate continues to stretch and compress into the Eurasian plate. So how the Himalayan mountain range was formed all was started with tectonic plate movement.