Missouri Rule 81.12 sets out what is included in the Record on Appeal, but basically it is the Transcript from the trial, Exhibits entered into evidence at the trial, and the Legal File. The Legal File consists of things like the information charging the defendant with the crime, any important motions argued before trial, and jury instructions.
That means that if something was not presented to the trial court by the defendant’s trial attorney, the defendant’s appellate attorney cannot talk about it on appeal. For example, if a defendant tells his trial attorney that he has a phone recording that could help his case and the trial attorney does not try to admit the phone recording into evidence, the appellate attorney cannot tell the Court of Appeals about the phone recording.
Sometimes, a trial attorney tries to get evidence such as phone recording into evidence but the trial court will not admit the evidence. In a jury trial, that means that the attorney wants to play the recording for the jury but the trial court won’t let the attorney play it for the jury. If that happens, the trial attorney needs to make an offer of proof.