Here's some typical job profiles in case this helps:
Computer programmers (software engineers):
https://www.prospects.ac.uk/job-profiles/software-engineerAccountants:
https://www.prospects.ac.uk/job-profiles/chartered-accountantBut really, don't worry if you still don't know what you want to do with your future - Most people in school, college and university have no idea what they want to do with their life or what kind of career would suit them, and a lot of people don't really figure it out until sometime in their 20s or even 30s. I honestly had no idea what I wanted to do after A-Levels letalone during GCSEs, and plenty of my friends didn't really know themselves either.
I'd recommend choosing subjects that you think you'll enjoy and be successful in - there's a lot of work to do to get the best grades regardless of the subject you pick; If you can aim to score A or A* then that's great because better grades will help you open up better opportunities when you finish - whether that's for applying to University, or some kind of Higher Apprenticeship.
A lot of universities are actually fairly flexible on entry requirements anyway - although a lot of 'STEM' degrees (Science, Technology, Engineering, Maths) at higher-ranked universities need A-Level maths, so if Maths is a subject you enjoy and you're interested in computers/programming or accountancy/finance then Maths is an obvious choice. (And if you enjoy programming then Computer Science would make sense at A-Level too, but it's not essential)
You're at least a couple of years away from really needing to worry about choosing a career anyway. Actually a lot of university graduates end up working in jobs which aren't related to their degree - the choices you're making now aren't going to prevent you from changing your mind later (although again, A-Level maths is probably the one subject which really makes a difference in keeping options open). Some people don't even go directly into university anyway and decide to take a gap year for a job or a bit of travelling while they figure out what to do next.