PSA: hotkey for screenshot in windows 10 is (windowsLogoKey)-shift-S

Then you click and drag to select a rectangle.

It’s basically a shortcut to the Snip program.

After you’ve captured the screenshot, you can:

• just hit ctrl-V to paste it into any place that can accept a pasted image: email, some chat programs, google drive, Paint, etc
• Click on the notification in the lower right. If the notification has already disappeared (it fades away after a few seconds), you can click on the Notifications icon (looks like cartoon chat bubble) in lower right and it’s in the list that shows.

If you click on it in notifications you get a whole window dedicated to editing the screenshot — drawing on it, cropping it, adding text — and then from there you can save it to a file or copy the newly edited image to your clipboard