1. Use Paragraph Dialog Box Settings: Select the paragraph for which you want to set line spacing, right-click and select the paragraph. In the pop-up dialog box, click the Indentation and Spacing tab, select a fixed value in the line spacing option, enter 30 points in the setting value, and then click OK.

2. Use shortcut key setting: select the paragraph to set the line spacing, click Alt+O+P on the keyboard, select a fixed value in the pop-up dialog box, then enter 30 points in the setting value, and click OK.