You can't change an ordinary copy of an official document into a certified copy. You can get certified copies of official documents from the agency that issues or records the documents. For example, you get certified copies of a will from the probate court.
A certified copy is a copy that has been stamped (usually with some type of seal that produces raised lettering or symbols) to verify that it is an original document, and verifies that it is not a "photocopy" that could perhaps be altered by someone else.
I thought there was some way I could attach a statement to a document that says I have examined the original and this copy and certify this is a true copy. Like I have an original will that will never be probated and was never recorded. How do I get a certified copy of that? The original attorney died years ago.
Every piece of property in the estate was jointly owned with the sole beneficiary so there is nothing to probate. However, there does need to be a certified copy of the will attached to the 706 federal estate return. Do we have to go through probate for the sole purpose of certifying the will. That seems sort of sad.
Yours is a unique situation, certainly. You are right, there seems to be no need to probate the will just for this small matter. Obviously, you can't submit a "certified copy" if there is no way to obtain a certified copy, but sometimes you wonder if the people at the IRS could fully understand a common sense statement like that.
If I were you, I would just attach whatever copy you have of the will (just so they can examine it to see what it says) and either make a handwritten notation on the will that there was no need for the will to be probated because the property passed through being jointly owned, or submit a typewritten letter that explains this. Or better yet, submit any documentation that would verify that the property was jointly owned, with at least one or more of the pieces of documentation being certified, if that is possible. If it is not possible for the documentation to be certified, then just go ahead and submit what you have and don't worry too much about it.