The first answerer is correct in that you do need to obtain a qualification like ACCA or CIMA in order to be a *qualified* accountant.

However, you are only eligible to take these courses if you already have a Bachelor’s degree in Accounting, Finance, or a related subject from a recognised university, so this needs to be your first step. Just do some research - there are many universities that offer qualifications like this - you could perhaps find one near you that offers evening classes, or maybe you could try the Open University or another university for correspondence courses. It’s doubtful that you’ll find any course that’s solely taught online though - almost all courses will require you to at least attend the university for exams if nothing else.