You need the IELTS UKVI (general) test which is provided by the British Council specifically. It's the same exam, but stricter facilities. The 'normal' test won't be accepted by the Home Office.
General, Academic is when you pursue higher education. I believe even only from Master's level onward, for a Bachelor's the general is sufficient. And if you do get a British Bachelor's, you don't need to provide anything else for a Master's. So that's really only for foreign graduates who are pursuing an advanced degree course in the UK.
Not answering the question but if you studied in English outside of the UK it may be enough. But you need to certify that you studied in English through https://www.ecctis.com/visasandnationality . That is how I did it, and I think it is easier and can be quicker.