Can you certify copy ANY document from ANYWHERE or just US documentation?
If the document you present to the clerk is a verifiable original (raised seal, notary stamp, etc.), they will be able to certify the copy. Country of origin should be a non-issue.
Of course, sometimes it depends on who is helping you that day! We all know how that goes, huh?
The only thing the clerk cares about the document is that it is an original ... not a copy. They then create a certified copy. The whole idea is, once that certified copy exists, you have an official "snapshot" of the original. This by no means implies the clerk knows for a fact the document they copied is 100% authentic. Only that the document you presented was an original, and it looked exactly like the copy they have on file.
This process was recommended for my DD214 Separation Form from the military. You are given 2 onion-skin "originals" (carbon copies) ... one with the type of discharge at the bottom, and one without. Since it is a difficult, if not impossible, task for the government to provide a replacement, we were given the advice to have the DD214 registered with the clerk of deeds in our county and to keep certified copies for our own records. Easy, quick, and relatively cheap "insurance" against loss of vital records.