Hi there! I plan on doing IT/software engineering as well so I can share my experience with work experience. (I'm in Year 12 and did some in yr 10 and 11)
Like _Anonymous explained, it's basically to help you experience how the career is really like for a week and see if you like it or not
You can choose where you go however some schools have a set week on when you go (my school didn't so I basically just chose any week in the year I wanted, however my sister's school had a set week where everyone went. If there's a specific place you want to go that has it on a specific week, you can try arrange it with careers advisor)
I went to 3 places
1) TATA Consultancy Services - a large IT consultancy company
A run-down on what I did:
-We toured the building and checked out the work environment.
-Did a lot of "business meetings" with important people such as managers, clients of the company, the CEO etc. Really we just listened to what their job was like and asked questions. It's also a great opportunity to get to know important people and have a headstart in networking
-Did workshops on interviews, programming, presentation, resume building
-They gave us a problem and we worked over the week as a group to present our solution to the client (Westpac managers)
I think this place relates to IT most but does also explores the business side of their work. Their program focuses a lot on improving your employment related skills with some taste of IT
2)Academy of Interactive Entertainment (AIE)- a school for game, animation development
Stuff I did:
-Learn the basics of a lot of programs that they used. (kinda like a class)
-Met with some past students and current students to check out their work
-Again gave us a problem and we had to present a solution to it
Here I felt more like I was at school rather than the workforce but it was fun
3) Nursing at a hospital
-Here I followed around different nurses in each ward and helped out with their work
I suppose you aren't as interested in this but its good to try out a different career (I wasn't sure if I wanted to go health or IT so I tried this out as well). Even if it's not related to your career in the future, the things you learn in it will be still valuable to employers! For example if you did work experience at a hospital, it shows you have experience in working with a range of people!
You can apply for these places online. Some other places might not have a specific work experience program so you can call them up or ask them directly about it (Usually these just involve you following someone who works there and helping out with their job from what I heard). You could also ask your careers advisor about whether they know of any places because many places ask careers advisors to share their work experience programs ( they'll be probably arranging the paperwork for you too so don't hesistate to ask them)
Good luck!