A governor is, in most cases, a public official with the power to govern the executive branch of a non-sovereign or sub-national level of government, ranking under the head of state.

- Governor, Wikipedia as on 8th January 2018

In India,

The governors and lieutenant-governors of the states and union territories of India have similar powers and functions at the state level as that of the President of India at Union level. The governor acts as the nominal head whereas the real power lies with the chief ministers of the states and their councils of ministers.

Article 157 and Article 158 of the Constitution of India specify eligibility requirements for the post of governor. They are as follows:

A governor must: be a citizen of India, be at least 35 years of age, not be a member of the either house of the parliament or house of the state legislature, not hold any other office of profit.

- extracted from Governors of states of India, Wikipedia as on 8th January, 2018

Thus, the Governor is a person appointed by the President. He is the executive head of the state, besides responsible for some other duties as well.