Not legal advice
This describes how the process generally works. Deadlines in your case may differ. If something has been filed against you, talk to a lawyer.
Appealing a records denial
A form exists, but you are not required to use it. Here is what an appeal must contain.
Submit through the Government Records Office
Utah Administrative Code R13-2-7(2) notes that an appeal form may be obtained from State Archives, and then says something worth knowing: an appellant is not required to use an appeal form so long as the information required by Section 63G-2-401(2) is provided.
So a letter containing the right elements is as good as a form. What matters is the content and the deadline, not the format.
Mediation first is usually free and sometimes faster
The Government Records Ombudsman mediates disputes between requesters and agencies at no cost. Requesting mediation also suspends the clock for judicial review, which makes it worth doing even when you expect it to fail.
If a vexatious requester petition has been filed against you
That is a different proceeding with different deadlines, and the most important one runs backward from a hearing date rather than forward from a filing.