The phrase "a formal document" is correct and usable in written English.
You can use it when referring to a document that follows established conventions or protocols, often used in official or professional contexts.
Example: "Please submit a formal document outlining your proposal for the project."
Alternatives: "an official document" or "a legal document".
He indicated that he was seeking a formal document to cover those issues.
The pope will consider their ideas over the next year or so, then respond in a formal document.
The Commodity Futures Trading Commission is planning to issue a formal document that spells out some of the agency's due dates.
"Candidly, what Barbara Joyce would have anticipated seeing was a codicil to the will, a formal document, not something with oil stains on it".
But when she remarried, and became pregnant, he had her jailed, saying he had never given her a formal document of divorce.
Such a will is a formal document that permits a person to record desires for how the end of life should be handled.
Since 1996, the city has had a formal document designating which agency would take the lead, although the document has failed to prevent jurisdictional clashes.
Envoys from the two countries will meet on Thursday in Geneva to confirm that they are in agreement, and a formal document could be signed next week, said Georgia's deputy foreign minister, Sergi Kapanadze.
A fatwa, or edict, is usually a formal document, signed and witnessed and given under seal at the end of a legal proceeding, but this was just a piece of paper bearing a typewritten text.
When the MTF made its original "statement of objections", a formal document listing its reasons for making an in-depth investigation of the deal, it noted one main problem.
Passport, a formal document or certification issued by a national government identifying a traveler as a citizen or national with a right to protection while abroad and a right to return to the country of citizenship.
