Not a stupid question, we all had to learn this at some point!

You’ll have to check the website. In some cases (such as FreeTube) you’ll get a notification inside the app itself to go download the update. It’s still up to you to download and install though.

You’ll run into the same issue using a terminal. Your Software Manager is just using apt and/or Flatpak under the hood anyways.

If you’ve installed a deb/appimage/tar/etc manually, it’s also up to you to keep it updated manually.

Your client is still Windows Store exclusive? That’s a hard pass from me.

It’s always sucked for them, and it always will. That’s why we make accommodations for them, like extra time or a smaller/move private exam hall.