How the typhoon begin?

Question

How the typhoon begin?

Answer 1

Are you asking how "A" typhoon begins or a specific one...other than that I would say pixie dust made it happen.

Answer 2

Typhoons are just one of the sub-categories in the major category of sea-based storms called tropical cyclones. The formation of tropical cyclones is still a matter of debate. Generally there needs to be a big contrast between air and sea temperatures, plus prevailing winds to stir it all up.  

Here's an excerpt from Wikipedia describing the key ingredients thought to be necessary to form a typhoon or tropical cyclone:

"The formation of tropical cyclones is the topic of extensive ongoing research and is still not fully understood. While six factors appear to be generally necessary, tropical cyclones may occasionally form without meeting all of the following conditions. In most situations, water temperatures of at least 26.5 °C (79.7 °F) are needed down to a depth of at least 50 metres (160 ft); waters of this temperature cause the overlying atmosphere to be unstable enough to sustain convection and thunderstorms. Another factor is rapid cooling with height, which allows the release of the heat of condensation that powers a tropical cyclone. High humidity is needed, especially in the lower-to-mid troposphere; when there is a great deal of moisture in the atmosphere, conditions are more favorable for disturbances to develop. Low amounts of wind shear are needed, as high shear is disruptive to the storm's circulation. Tropical cyclones generally need to form more than 555 kilometres (345 mi) or 5 degrees of latitude away from the equator, allowing the Coriolis effect to deflect winds blowing towards the low pressure center and creating a circulation. Lastly, a formative tropical cyclone needs a pre-existing system of disturbed weather, although without a circulation no cyclonic development will take place."