Should I add the "presenter certificate" to the paper presented at a conference? I have presented a paper at a conference and received a certificate proving that I was a presenter.  The conference does not have an English agenda, so it would not be easy for an application committee to find proof that I was the one who presented it online.  I am now submitting the paper as one of my writing samples for a Ph.D. application.  Should I attach the presenter certificate to the paper, in order to prove to the committee that I was really the one who presented it?
As per the answer to your previous question, you are not required to spontaneously supply proof for everything in your CV, and it would look extremely unusual to attempt to do so in this case. 

The fact that you could be asked to substantiate anything written in your CV, and the consequences of subsequently being caught in a lie, are considered enough of a deterrent to prevent people from lying about their credentials. The standard practice in academia is not to include "proof" of everything on a CV unless explicitly asked for proof of some kind.

So in answer to your question of whether you should merge the "certificate of being a presenter" into the paper presented at the conference as part of your PhD application: No, you should not. You should not submit such a "certificate" at all unless you are explicitly asked for it, and I have never heard of anyone being asked for such a thing.