If you wanna host a file such as a image and video , photobucket is a very good option. It is a image sharing host. You can upload a file to photobucket and use the link to share it with others.
In windows you can search for keyboard from start menu and open keyboard settings. Or you can go to Settings > Accessibility > Keyboard. In the keyboard settings window, toggle the switch that says "Use the Print screen button to open screen snipping". Hereafter whenever you press print screen button, you will be able to make a selection on the screen for a screenshot.