Rony Aguilar López wrote:

Reading the Bible, it is easy to prove that this is year 6000, the 120th Jubilee.
Why do people say this is year 5776 and the Jubilee?

Yes some people believe that we are at exactly 6000 years this year. However, there is great debate in the chronology.
However, it seems to me that the strongest supporters of the counting that notes our current year as 5776 are the Jewish People, who have used this calendar for hundreds, perhaps thousands of years, and are the only society (as per my research) that claim to count from Creation.
As far as the reasons for why this Jewish year might be a Jubilee, please see our series of articles in Breaking Israel News on the Mystery of the Lost Jubilee.