As we know that NTA will be conducting JEE Main twice a year from 2019. One exam will be held in January and the other one in April. You can give both the attempts and the result would be based on the score of better of two. If we talk about the total number of attempts since no guidelines have been issued regarding this and earlier 3 attempts were given so let's assume that a total of 6 attempts for JEE Main will be given at the rate of 2 attempts per year.
As of now you have the eligibility to appear in JEE mains till 3 times coming to the new method it has not been confirmly declared that JEE mains will conduct two times in a year.