The New buddy feature in Pokémon Go is awesome.
This new feature allows you to collect candy for your hard to find Pokémon like Snorlax so you can power them up.
For example lets say you caught a cool Lapras and you haven't caught any more since, well you can't power him up without any additional candy. This is where is comes in handy, just add the Lapras as a buddy and walk around soon you will see a pop-up that says they added some Lapras candy without you having to catch a Lapras, how cool is that.
You can add your buddy by clicking on your avatar on the lower left of your screen then clicking on the the green circle 
and selecting add buddy, choose the Pokémon you want as your buddy and then get to walking.
If you select your avatar again when you are on the main screen and then click again you will see how much you have to walk until the candy will arrive.
The New buddy feature in Pokémon Go is awesome.
and selecting add buddy, choose the Pokémon you want as your buddy and then get to walking. 
