Sharing documents and forcing them to make a copy

I want to share the documents that I make with other teachers. I was practicing with my own two emails. When I send a doc to my other email and annotate on it. It changes the original. How do I make it so that the teachers that I share it with do not change my original document? I apologize if this has already been covered.

When sharing a document, I make sure the document is view only so that the recipient must make a copy in order to annotate. I can also change the url to force a copy by deleting the ending up to the slash, then adding “copy” to the end. ex: https://drive.google.com/file/d/0B2O6Y8naU8budTFPYkd5NjljeU0/view?usp=sharing
https://drive.google.com/file/d/0B2O6Y8naU8budTFPYkd5NjljeU0/copy

Hope this helps!

I am having the same issue. The document is set correctly so that they can only view but a few select students can annotate on the original. Those annotations stay on my original!