You can assign a shortcut key (F1—F8) to a paragraph, character, or list style, and then use the shortcut keys on your keyboard to apply a style to your text.
Note: To use shortcut keys on a portable computer, press Fn with the shortcut key.
Click any text in the document.
Click the paragraph style name at the top of the sidebar on the right.
If you don’t see a sidebar, or the sidebar doesn’t have text controls, click
in the toolbar. If the text is in a text box, table, or shape, first click the Text tab at the top of the sidebar to see paragraph styles.
Do one of the following:
For a paragraph style: Click the paragraph style name at the top of the sidebar, move the pointer over the name of the style you want to assign a shortcut to, then click the arrow that appears.
For a character style: Click the Character Styles pop-up menu, move the pointer over the name of the style you want to assign a shortcut to, then click the arrow that appears.

For a list style: Click the Bullets & Lists pop-up menu, move the pointer over the name of the style you want to assign a shortcut to, then click the arrow that appears.

Choose Shortcut, then choose a key.
Now, the shortcut key appears next to the style name in the menu for easy reference.
To remove a shortcut key assignment, follow the steps above, then choose None from the Shortcut menu.