Thumper, welcome to the Community!
Probably the most used software is Adobe Illustrator, which is certainly very robust and powerful, but requires a monthly subscription.
Inkscape is free, but can be challenging to learn. (But does some things that alternatives don’t, so I always recommend having it installed).
While I started with Inkscape, I pretty quickly decided I wanted a powerful (and IMHO easier to use), but inexpensive alternative.
Based on some others’ recommendations, I tried the trial versions of Serif’s Affinity Designer (which has many of the functions of Adobe Illustrator), and Affinity Photo (similar to Photoshop).
These currently have, I believe, a free 30-day (or longer) trial, and are also on sale (for at least a few more days, I believe) for $24.99 each (Regular price $49.99 each). That price is for unlimited copies of each on a single (Mac or WIndows) platform. If you have both platforms, then you would need to purchase one license for Mac and a separate one for Windows. They also have iPad versions of Designer and Photo, which are regularly $19.99, and now are just $9.99,
Hope you find these helpful - I’d highly suggest getting the free trials, and then deciding if it is worth spending $50 or so (per platform) for the programs.
(No, I don’t work for them, I’m just a big fan!)