Taking Screenshots in Unity

Hi, I began working in unity a couple of months ago and I'm nearly ready to finish my first game. What I need now is to promote it before release. Because the best way to promote is social media I need a way to take screenshots and publish them. But the problem is that when i take screenshots with sniping tool, photoscape and other utilities, the quality of them is much lower than inside the game. Is there a way to take screenshots directly from Unity editor or even when the game is exported

Thanks in advance