テキストを \flushright で囲めば良い。
例
\begin{flushright} Lorem, ipsum dolor sit amet consectetur adipisicing elit. Ab laudantium velit atque! Recusandae ratione, consequuntur perspiciatis totam nemo assumenda eius omnis veniam quas aperiam a cum adipisci ducimus mollitia? Ea suscipit dolore minus cupiditate ullam. Corporis vel saepe fugiat ullam ipsa quasi aut voluptate blanditiis! \end{flushright}
結果
![](https://hanjouchan.org/wp-content/uploads/2020/11/screenshot-2020-11-24-at-18.41.58.png)