Question: I'd like to see the number of visitors on a specific page (for which I have URL).
I don't find in Analytics where to enter a URL in order to look for statistics for this specific page.

Answer: 
Go to Behavior > Site Content > All Pages and put your URI into the search box.![enter image description here](https://i.stack.imgur.com/36k4C.png)
As Blexy already [answered](https://stackoverflow.com/a/19502866/1476885), go to "Behavior > Site Content > All Pages".

Just pay attention that "Behavior" appears two times in the left sidebar and we need to click on the second option:

           [![sidebar](https://i.stack.imgur.com/1pSaO.png)](https://i.stack.imgur.com/1pSaO.png)