It's a very common and versatile phrase used in various contexts to express complete negation or disagreement.
Here are some examples:
* "Est-ce que tu as aimé le film?" (Did you like the movie?)
* "Pas du tout." (Not at all.)
* "Tu es fatigué?" (Are you tired?)
* "Pas du tout." (Not in the least.)
* "Tu veux du café?" (Would you like some coffee?)
* "Pas du tout, merci." (Not at all, thank you.)