Skype Free Download 5.0 For Windows 7

During video calls, Skype and Google Meet only let me share the whole screen (desktop) rather than specific windows. The only option it shows is the Desktop screen as if I didn't have any other windows available to share. I'd appreciate it if you could give me a hand, as I give online classes through video calls, and not being able to share individual windows during them it's quite annoying.