Forced regeneration

A forced regeneration was an instance of regeneration that was imposed on an individual when they did not choose or need to regenerate due to injury, usually as a form of punishment. reminded the Thirteenth Doctor that it was the "ultimate sanction" for breaking the Time Lords' laws. (TV: The Power of the Doctor)

"Forced regeneration" should not necessarily be conflated with regenerations that were brought about voluntarily without an injury, such as (according to some accounts) that of Romana I to Romana II, (TV: Destiny of the Daleks) nor with executions that happened to result in a regeneration, such as that of the First Malika. (COMIC: Omega)

Instances of forced regeneration
The chronologically first known forced regenerations were also some of the first regenerations known at all, those forced by Tecteun onto the Timeless Child in order to extract the secret of regeneration. Tecteun experimented with at least five regenerations of the child, and used the discovery to allow herself and later others to regenerate. (TV: The Timeless Children)

The Second Doctor's sentence for his trial for stealing the TARDIS and breaking the non-interference policy was to forcibly take a new face and be exiled to Earth. (TV: The War Games) Though the Celestial Intervention Agency was able to delay the execution of this sentence for some time, (PROSE: World Game) the Time Lords eventually sent animated scarecrows to carry it out. (COMIC: The Night Walkers) The TARDIS was sent on a programmed trip to Oxley Woods and the Doctor had his knowledge of how to operate or repair it blocked off. (TV Spearhead from Space, The Claws of Axos)

In the Inferno universe, the Second Doctor was also forced to regenerate but chose a different face, possibly that of the Leader. (PROSE: Timewyrm: Revelation)

The Twelfth Doctor used regeneration as a means to incapacitate the Eleventh General in order to allow himself and an extracted Clara Oswald to escape the extraction chamber. The Doctor did this due to the gun not having a stun setting and had the General confirm that he was on his tenth regeneration (eleventh incarnation). (TV: Hell Bent)

As part of his so called "Master's Dalek Plan", captured the Thirteenth Doctor and forced her not only to regenerate, but to do so into becoming him. The Master acknowledged that the Doctor had been subject to forced regeneration "once [or] maybe more than once". The Doctor's new body maintained the appearance, memories and personality of the Spy Master, while his original body became lifeless. The Thirteenth Doctor found herself at the Edge of Existence, where she met the Guardians of the Edge. They confirmed to her that because she had not yet passed the Edge, the forced regeneration was incomplete, and that post-regenerative trauma to the body was more likely. The AI hologram of the Doctor (who was knowledgeable about the concept of forced regeneration) alongside Yasmin Khan and Inston-Vee Vinder were able to reverse the forced regeneration, in what the restored Thirteenth Doctor called a "forced degeneration". The Master was returned to his original body, which was severely weakened due to the double transfer and his body's lifelessness. (TV: The Power of the Doctor)