It is an approach to teaching language based on the idea that if you have to do something physical in response to language, then learning is more meaningful, and you learn faster.
Example
The learners are looking at action verbs. The teacher says 'Jump!' and they jump; the teacher says 'March!' and they march, etc.
In the classroom
Many teachers integrate TPR with other approaches and techniques rather than using it alone. It is useful, for example, for teaching body vocabulary, prepositions, and language for directions, and may be particularly suitable for low level learners, learning more concrete language.
Further links:
https://www.teachingenglish.org.uk/article/total-physical-response-tpr
https://www.teachingenglish.org.uk/article/using-flash-cards
https://www.teachingenglish.org.uk/article/stirrers-settlers-primary-classroom