Sure, let's see what we've got. The link was this: Adobe Creative Cloud system requirements
There's a lot on there but let's scroll down to where it says Desktop Applications, and then click on Illustrator. To save you time, that takes you here: Adobe Illustrator system requirements . These are the requirements today (they keep changing). Notice you've got to skip over the Windows stuff until you come to where it says macOS.
I've added my comments in brackets [like this]
macOS
- Multicore Intel processor with 64-bit support [a Macbook air will be fine for this]
- macOS version 10.12 (Sierra) or Mac OS X version 10.11 (El Capitan) [this is the one where most people fail right away. You MUST know what version of Mac OS you have, because software is only going to work on some versions of the system. The system (Mac OS) is much more important than the specific computer. Use ABOUT THIS MAC to find out the system.]
- 2 GB of RAM (8 GB recommended) [Also use About this Mac]
- 2 GB of available hard-disk space for installation; additional free space required during installation (cannot install on a volume that uses a case-sensitive file system or on removable flash storage devices) [Also use About this Mac]
- 1024 x 768 display (1280 x 800 recommended) [A Macbook air will be fine]
- Optional: To use GPU Performance... [this is optional so we'll ignore it]
- Internet connection and registration are necessary for required software activation, validation of subscriptions, and access to online services.*
So, about this Mac is the key. Don't know where it is? Click the Apple at the top left of the screen, and a menu appears. It's in there. Might say about this Macintosh, or Mac, or Computer.