I think you can do that with the default app but I don’t use Ubuntu/Gnome and may be wrong. I hope this link may give you a starting point: https://www.tecmint.com/take-or-capture-desktop-screenshots-in-ubuntu-linux/
I think you can do that with the default app but I don’t use Ubuntu/Gnome and may be wrong. I hope this link may give you a starting point: https://www.tecmint.com/take-or-capture-desktop-screenshots-in-ubuntu-linux/