In this reaction, the addition of \(HCl\) takes place on doubly bonded carbons following Markonikowff's rule. The \(H^+\)will attack on the doubly bonded carbon atom of the alkene and not benzene because benzene has delocalized carbon atom.
Here, the \(H^+\) will form a secondary carbocation that is more stable than the primary carbocation. After hydride shifts from the secondary carbocation, a benzylic carbocation is formed, which is more stable.
