Please, please, please read the pages I've linked.
Do not use direct formatting. There are a plethora of built-in styles you can use. They can be modified.
There is a built-in style named "Quote" that you can modify for your use.
Paragraph styles cannot be applied to less than a paragraph. If you want a style to apply to part of a paragraph use a Character style. Two built-in character styles are Strong and Emphasis.
The term "paragraph" in Word refers to anything that is followed by a paragraph mark. This includes blank paragraphs.
Basic concepts of Microsoft Word: An introduction by Shauna Kelly, MVP