The phrase "a joint document" is correct and usable in written English.
It can be used when referring to a document that is created or agreed upon by two or more parties.
Example: "The committee submitted a joint document outlining the new policies for the organization."
Alternatives: "a collaborative document" or "a shared document".
The following June, Mr Blair succeeded in launching a joint document: Third Way - Die Neue Mitte - with Gerhard Schröder.
The participants had been expected to come out about an hour ago, but instead are beavering away on a joint document.
In an effort to secure Belgrade's backing, Kosovo's administration had offered a joint document aimed at reassuring Serbs that it was committed to improving their living conditions.
Russia's Dmitry Peskov said after Friday's talks that work was continuing on a joint document.
He will issue a joint document with Japan after Wednesday's summit talk, the fourth such landmark document issued between the two countries.
This month, UAR and more than 40 science organizations will publish a joint document, or concordat, laying out how they plan to be more open and transparent about their animal research work.
No details of the draft were available, and negotiators have suggested that any joint document emerging from this round of talks would probably be a broad statement of shared principles that left the most divisive problems for future discussions.
Instead, the sides will work on a possible joint document that will also take into account the proposals of Ukrainian President Petro Poroshenko.
"Based on the proposals made by the French president and the German chancellor, joint work is being done to prepare a possible joint document about implementing the Minsk agreements," Peskov said.
Dai supported the idea of a "concise and substantive" joint document to be issued in conjunction with the visit.
National quirks, historical practices, varying constitutional norms, the influence of parliaments: war and peace seem ultimately unsuited to a joint European document.
