I don't send copies of my documents to anyone. Period.
I have a good reason for this. During a consulting trip to China, I was asked to review a number of applications for teaching positions. To my surprise, I found myself reading my own resume, only with someone else's name. And all the supporting documents were mine, photoshopped.
It is an unfortunate situation that is getting worse. Many, if not most, job postings are not to find good teachers, but to glean good documents.
I don't mean to say that YOU are guilty of this, but please understand my caution. My credentials are worth a fortune to someone without the ability or ambition to get their own.
I will be happy to work with you to verify that I am what I say. There are lots of ways to do this that protects us both.
Example for Chinese jobs: Here at the University of Oregon we have 300 Chinese students, undergrad and graduate. I have been a host family to many, and they could act as your verification agent, examining all documents and talking directly to you.
Once hired, I will bring the needed documents with me.
And I will require verification of who you are, too. That's only fair, right?