Which itr need to be filed?

As per income tax act, income earned by priest as salary comes under the head salary and by doing pujas comes under the head Profits and Gains from Business or Profession as the individual is in the profession. So, you have to file ITR 3. But most of the people file ITR 1 by showing the same in income from other sources. But in income tax act it was clearly stated that profession includes vocation and priest comes under vocation. So, I recommend ITR-3.

You can file ITR 4 online. But I think in this case you can't file ITR 4 under 44ADA as this profession is not covered under 44AA