What exactly do Software Developers make? What type of companies do they work at & who are their clients?

When i think Software engineer/developer i typically think of someone who works in front of a screen all day — trying to create a new feature on a website for their client.

Who exactly are their clients? Is it typically big corporations/insurance companies? Is it ever anything fun like Facebook, Coca Cola or Disney? Are the clients ever a small mom n pop store – like a local restaurant that wants a website?

How long are such projects? For example if their client is Disney, does the software engineer have a 2 week deadline to create & debug the system features that Disney requested?

And lastly, what are said "features" that developers develop? Are they like a new tab on the website or a new app?

I applogize if said questions are "out there". I have very little knowledge on the front & im hoping this subreddit community could help me out.