In Bootstrap 3 and Bootstrap 4 you can use the following:
<p class="text-justify">Justified text.</p>
Official documentation
(Update) This feature removed from Bootstrap 5
- Commit
- Official document and recommendation
Note that we don’t provide utility classes for justified text. While, aesthetically, justified text might look more appealing, it does make word-spacing more random and therefore harder to read.
Based on the official UX suggestion: don’t use justified text! 😉