An episode monologue (also called opening- and ending monologue) was a concept sometimes used in television and audio stories to set up and close up the scenery of certain tales. It is most often given by the main character of the story.
Monologues were a regularly used instalment in the Doctor Who spin-off The Sarah Jane Adventures to open and close each season. For the spin-off's last season only three stories were produced due to the untimely passing of Elizabeth Sladen, and a closing monologue for that season hadn't been made by that point as a result, and therefore stock audio had to be reused and modified to make up a ending monologue. Each monologue was spoken by Sladen as Sarah Jane Smith.
In the first part of The End of Time, an opening and ending monologue was spoken by Timothy Dalton's Rassilon. In-universe, this was a speech given by Rassilon as he stood before the High Council of Time Lords on Gallifrey during the last day of the Last Great Time War.
Doctor Who's series 12 episode 6 story Praxeus had an opening and ending monologue spoken by Jodie Whittaker's Thirteenth Doctor.