Given the technology readily available to anyone, see creating false documents is quite easy. Even so, some people elect to use old technology such as copy machines and typewriters to create a forged document that appears to be real. In a recent case that was heard in Los Angeles Superior Court, a plaintiff either created or had someone create a fraudulent deed of trust using a copy machine, a sharp instrument, and a typewriter.
To the naked eye the deed appeared authentic. I scanned the front and rear of the deed at high resolution.
The scanned images were enlarged in Photoshop. The result was the altered document, fraudulent deed, was apparent. The ghost of the original numbers was visible below the typed numbers.
Ask your prospective document examiner whether they have equipment capable of discovering difficult to identify alterations in documents.