Will an Executive MBA be enough or not? I have completed my engineering in 2011. Now I am working as a HR manager in an IT company.

Dear friend, Relating to your job profile, I would like to suggest you, to boost you further career with opportunities and promotions, Executive MBA is the best option for you, where you can pipe up your seniority. In a current market, the value of Executive MBA holder is greater than a fresher MBA

Yes, an executive MBA will sharpen your skills in the HR field and assist you in a better understanding of the concepts of modern HR practices. Along with executive MBA, you should also try and get some certification done in specialised HR sub-domains.