Hi!
I'm not sure about VCE Art as my school doesn't offer it but in general, Visual Communication is like design (graphic design, architecture) whereas Studio is more like the artwork you see in galleries and I think there's a focus on 3D Art (resin work, sculptures, clothing) rather than drawings and paintings.
If you want to see some of the work from Art or Studio Art, look up 'Top Arts NGV 2017' although check whether the piece is from Art or Studio Art because they're all jumbled up.
You have to do a folio for both Viscom and Studio (not sure about Art). In Viscom, the folio is worth 40% of your mark. In Studio, the folio and final artwork is worth 60%. Generally Visual Communication students will work on the folios longer than Studio students because the final piece in Studio also takes a lot of time so their folios are due earlier and are not as long as the Viscom ones.
If you like technical work, design or are more science/math inclined, I'd suggest Viscom. If you like having lots of freedom with your work, I'd suggest Studio or look into Art. They're all great subjects though!
If you want to know more about the subjects, I'd recommend looking up their study designs on the VCAA website (especially for VCE Art).
Hope this helps!!