write the mechanism involves in markovnikov addition

Dear Student,

According to Markonikov's rule, while addition of hydrogen halides to an unsymmetrical alkene, negative part of the addendum (adding molecule) gets attached to that carbon atom which possesses lesser number of hydrogen atoms.

(I) is the major product. 

Mechanism is as follow:

In other words we can say that, according to Markonikov's rule, product formation takes place via more stable carbocation. 

Hope it helps!