Mac Apps

Hi everyone. I realize this might be a rather odd question given the scope of this comm, but here goes anyway. I need to know if there is any way of taking a screenshot on a Mac. Please allow me to elaborate. I recently registered on a job-related website which is similar in scope to LinkedIn, but with some differences. For one thing, this site is a bit more accessible with Apple's on-board screen reader than LinkedIn. Or at least most of it is. Here's the part that is not accessible, at least as far as I can tell. I've logged into the site to post some comments and do a couple other things. However, the site automatically logs me out only after 5 or so minutes. I've tried contacting them about this, but nobody has responded. Hence my need for a screenshot. There is not even an indication that the site is automatically logging users out, or at least no audible indication. I'm not sure this issue is specifically related to the screen reader in use either, because I tried changing some relevant settings on my Mac but I'm still being logged out constantly. Here is a link to the portal to which I'm referring, but this seems to happen on all of AFB's sites. https://is.gd/wWdltg .