How do you print a player's ID to the computer?

Without putting the playerID there, how can you print a players ID, from the site, to the computer like

print("Hello world")

How can you print the userID of anyone?

You can do this by calling for the Player's UserId. Here is an example:

player = game.Players.bbissell --Path of the player
print(tostring(player.UserId)) --Prints string version of the UserId

If you are looking for a way to get the User ID by looking it up on the ROBLOX site, For instance, If I am not in your game but you want your script to get my userID, You are able to do that via HttpService.