Dota2 displays ping & FPS while in game

First right click on the "Dota 2" and select properties.

After you click on properties, this box will pop out and you now have to click on the "set launch options".

In the black of launch option type "-console". Click OK and launch the game. Following box will appear in your game.

Type "net_graph 1" and then click on submit. DONE!

Add-on: 

Normally the display will in the middle of the screen and it's annoying. Below is more settings for the display.

Changes height, how high on the screen it is: net_graphheight "840" 

Adds additional margin which is added to the height: net_graphinsetbottom "130"

Adds margin to the left: net_graphinsetleft "80"

To make the font small: net_graphproportionalfont "0"

net_graphinsetright "0"

net_graphinsettop "0"

This setting need to adjust according to your own screen size.