Applicable tax for software startup

Hi all. Me along with 4 of my friends started a Software Development company as Partnership firm. We all are employed in different companies and is working as part time here. We got a client from aboard and is billing approx 2000 USD per month. Please advice how we can manage our income and tax. I have heard there is no tax if we bring in foreign currency. We have only client abroad and is being paid as USD. We are based in Kerala. Please advice.