Need information about your software

I have work with govt companies like Army,Defence and Air force they have no GST no can I enter there bill in your software and when I one time enter my sale company and purchase company I'm going to add another bill of same company can I need to re add the company or software automatically pic the company and its detail and some time we need to leave a bill no for later entry can it possible in it and some time we need to cancel bill because govt. company cancel the order can I cancel the bill