The simplest way I can explain it to you is really as follows:
IT - The
application of
existing technologies to solve business needs. So essentially things like database admins, IT helpdesk support, system admin, system/business analyst, project manager.. essentially bridging the role between management and technical.
CS - The
creators so things like artificial intelligence, system engineer, software design/development, programmer/game developer. In pretty much every CS course there is a chunk dedicated to high-level maths so this is another consideration.
Please note the above isn't explicit - just because you don't do CS doesn't mean you can't do something like AI for example... I wanted to illustrate the key differences.
From an academic standpoint - CS is maths heavy (for obvious reasons as per above) whereas IT contains a reduced amount of math (but its still there). I would encourage you to view something called a 'course map' (or if no course map is available, handbook entry) - every uni has them available just do a quick google search and it should come up. I've linked you a sample one from La Trobe below so you can see. There is overlap between the two degrees but also distinct differences.
https://www.latrobe.edu.au/handbook/2019/undergraduate/she/it-engineering/single-degrees/sbcs.htm - COMP SCI
https://www.latrobe.edu.au/handbook/2019/undergraduate/she/it-engineering/single-degrees/sbit.htm - IT
Some more links I found via a quick google search:
https://www.computersciencedegreehub.com/faq/difference-information-technology-computer-science/https://www.rasmussen.edu/degrees/technology/blog/it-vs-computer-science-degree-infographic/In general, you should be aiming for a course and uni that offers networking/industry opportunities such as industry placement/internships. This is really important for this occupation as for IT it's really more about this rather than purely your academic background. Getting your foot in the door is the most important thing and academic quals alone often don't do that. Anything to boost you/give you the edge will be great.
I hope this helps?