AI am a self-taught baker. My question is how can i have a smooth finish after covering my cake with fondant

Have you tried fondant smoothers?

ANo, i haven't. Where can i purchase one?

At almost any craft store that sells cake supplies.

And make sure your buttercream is really smooth underneath.

It helps tremendously to have a well-refrigerated cake when applying fondant.  Keeps your buttercream from squooshing around.

Smooth out air bubbled from the top first, then work your way down the sides gently but briskly. 

AThanks a lot, let me look for one