At the conclusion of an endoscopic procedure, we must prepare a report of the observed findings. However, the generated report is not only intended to describe and list what was detected during the endoscopy. The endoscopy report should serve as a relevant tool that not only improves communication among medical staff, but also supports subsequent clinical decision-making through a clear diagnosis. This objective can be achieved by systematizing our reports through the routine use of validated classifications and scales. Nevertheless, their use is often complex and not regularly applied, particularly among endoscopists in training. For this reason, we present the following narrative review, aimed at providing gastroenterologists in training with the most important classifications, explained in a simple manner and accompanied by updated references.