I recently bought a 6hp Yamaha outboard it had been sitting for roughly a year should there be anything I need to add to gas or any additive and should I do anything to it before I run it any type of cleaning...and yes it does run thanks

I wouldnt run any of the gas it came with, id dump that in a car or old tractor. I doubt its fuel injected correct? A can of seafoam wouldnt hurt. Is it a two stroke or a four? Id guess a two.

Time for a carburetor rebuild at ;least.

If it was maintained well in the past, it shouldn't need anything. Adding Seafoam or any other treatment couldn't hurt. If the fuel tank is in the motor, drain it and fill with a fresh mix. 

If it's been sitting that long without any sort of additive already in the gas, then ditch it and get fresh gas because it's too late to add anything to it. Adding some Sea Foam to the new stuff wouldn't hurt.

Carb 2 stroke looks like I'll be adding me some seafoam

if it is carburated, did not have the old gas run out of the CARB, then the pilot jet may be plugged. The indication will be that it wont run at idle with the choke turned off. It should start OK, then run ok til choke is turned off and then wont run right or dies at idle. If so then you will have to clean the pilot jet.